One of my daughter’s roommate didn’t have Facebook either. She met her roommate on move in day.
I dont find it unusual that you havent had a response yet, for the reasons already listed, but I do find it unusual that the school does not apparently host a message board for students to find roommates, and communicate on other topics.
Where I live kids just graduated last week then many go out of town. As you know the end of senior year is a busy time and emails about fall housing might be very back burner.
Some people LIKE asocial roommates. They find them easier to live with than socially demanding, clingy roommates.
A lot of students don’t check their new school email accounts on a regular basis. He could unavailable due to travel, etc. as many have mentioned. He could also be a foreign student. Believe it or not, there are other methods of social media out there. You’ve gotten good advice - relax and don’t worry. It will be what it will be. And you may have a new roommate by the time you move in anyway.
My first guess was that the roommate sounds like one of my sons. He was like Magnetron’s kid’s roommate (asocial, on the spectrum), Freshman year he had two suitemates–one was a preppy/golfer/frat boy, the other a Brony. They made it through the year just fine. My son is very quiet, clean/organized, considerate, easy-going–not a lot of fun, but an ideal roommate in many ways. My other two sons met their roommates at move-in. Even the more sociable one thought contacting them would be weird (like, that’s what girls do to plan their room decor. . .unnecessary for guys). It could be anything, though. Just wait and see.
Are you even allowed to change roomies at this point? If not, then I would try not to think about it. Hey, you may end up getting a single if he doesn’t exist! Lol! But if you are allowed to change, and you feel strongly that a person with no social media is not going to be the right fit for you, then make your move. You may lose out on the location so you need to consider that as well. Maybe call the housing department to see if the kid is still matriculating in the fall. He may have gotten off a weight list. Good luck!
Of course, maybe this missing roomie is on another forum complaining OP won’t stop trying to contact him and wondering what that reveals.
I wouldn’t worry about it.
All three years my S had random roommates he never contacted them prior to move in. As the Mom I thought this was strange but again the other roommates didn’t contact him either. Might be a male thing.
One of my kids does not use any form of social media but she does check her email. Another of mine has a Facebook but doesn’t use it and never read his email during his college years.
@atomom what is a Brony?
So I contacted admissions and it turns it they didn’t accept any ax murderers for the fall semester anyway!! What a relief. 
Brony = male fan of My Little Pony.
My son and his roommate did communicate some beforehand but not until several weeks after the assignments were sent out. My son got an emal, replied after a couple of weeks. They exchanged cell info and texted maybe 3-4 times. They seem to get along well and are rooming together next year. They don’t seem to socialize much but they certainly coexist fine.
My D hasn’t used Facebook for a few years now. She is on Instagram and twitter, but doesn’t use her real name, or anything close to it. So she’d be almost impossible to find, too. But she exists. And she’s not an axe murderer.
Your future room mate may be on social media but, like my D, doesn’t use his real name.
You’ll meet him on move-in day, so just be patient. It’ll work out.
S’s room-mate was an int’l student and he didn’t have ready access to the internet so Facebook etc… wasn’t part of his modus operandi. D doesn’t participate in any social media because she says it takes up too much time. So, two different reasons for not being on social media. Both of them met their room-mates on move in day and in both cases it worked out fine.
My D’s roommate last year wasn’t on social media. She had an email which she answered reluctantly. She seemed to have no interest in getting to know my D. As it turns out, the girl was just really shy, from a tiny town and really freaked out about leaving home. They ended up very good friends.
Social media is actually dying down for lots of young people. My 14-year-old texts his friends but will not sign up for instagram, snapchat… any of those things even though his sister begs him. He has a facebook that doesn’t use his last name and I’m not sure he’s checked it in the last 6 months. Most of his friends are not on social media either. They text when they want to talk.
Relax. I know you are eager and excited but not everyone is ready to jump into college talk right after graduation. Some really aren’t into social media. I didn’t even know my college roommate’s name until she walked into my room. That was fine too!
My kids abandoned Facebook, Twitter and Instagram when their grandparents got on them. They use Snapchat and GroupMe (?). They are not axe murderers so far.
If he is not replying to emails, he may not be checking them or he may have decided he is not attending. Maybe he checked you out on social media and thinks you look like an axe murderer 
S1’s roommate freshman year never responded to S’ s email. He was an international student and wasn’t on social media. RM didn’t communicate much once he got on campus (and in fairness, neither did S1) though RM did find friends at International House and made a community for himself.
Even more shocking, he does not have an account on College Confidential.
Many roommates do not meet until move-in day. Don’t worry about it.
First, I understand you are excited and want to get in touch and start your college adventure, but relax. Some students change their facebook name senior year, some people may be on vacation, and not everyone is on Instagram/Twitter (or at least under their own names). Take a deep breath. Try contacting your roommate through the school email and realize it may take a while to hear back. It is helpful to be in touch but there is plenty of time. Worst case, you figure things out when you get to school.
PS. In my day (which is likely your parent’s day) my freshman roommate and I did speak on the phone before we started and planned out some things in advance which was good.
My college roommate was listed on Facebook by her family nickname. Also, keep in mind that the names on applications and admissions materials are all legal first names. Some people go by their middle names and are more likely to have that on their Facebook profile if that is the name the use. (I know a William who went by Ross, his middle name.) Some people even go by a completely different first names for various reasons. (I knew a John who went by Jack to avoid confusion with his father who was also John.)