I am sorry this is happening OP.
No, there is not much you can do at the school you are deferred…write a LOCI and send to admissions and the coach. BUT…do you really still want to attend this school and play tennis for this coach? Again, still send the LOCI, but take time to reflect on this.
You can contact the coaches you had previous contact with and tell them you are still interested should they have openings (many schools’ teams are not fully recruited yet). If they previously knew you were ‘committed’ to X school just simply say you were deferred admission there and not sure it will work out. Do not complain about how X coach has wronged you.
You can also contact coaches you have previously not contacted, to see if they have openings on their teams.
I know this is difficult and stressful, but you must continue to move the ball forward at other schools over the course of the next several weeks. Contact other coaches today, before the holidays. Continue working on your essays and apps and stay on top of deadlines.
Good luck.