Let’s start with the basics:
Did you submit all of the required documents before the deadline?
Did your parents fill out the CSS profile that has the income and assets of both of your parents (if they live together)?
Did your parents fill out the CSS profile and the non-custodial profile (if your parents are separated, divorce or never married).
If you do a search on CC or a general search on Boston university, you will find multiple threads written by students and parents about BU giving them an unaffordable financial aid package.
Just because you are eligible for the maximum amount of aid, does not mean you will receive the maximum amount of aid because BU does not promise to meet 100% demonstrated need. The only aid that you are automatically entitled to is federal aid- PELL grants based on your EFC and Federal loans . BU has total discretion as to how they give out their money.
BU has gone on the record stating that while they are need blind in admissions, they are not talent blind when it comes to giving out their own institutional aid.
https://www.nytimes.com/2009/04/19/education/edlife/finaid-pappano-t.html
BU has essentially given you an admit-deny; they have academically admitted you while providing a financial aid package that pretty much assures that you will not be able to attend because it is not financially feasible option.
You will have to move on and go to your affordable choice