Mass has no right of redemption after the forclosure sale, so you're in a big mess at this point. Basically, you like alot of other people waited too long to get involved.
Your only option is it to get an honest attorney (if such thing exists

) This can only be resolved by a judge at this point.
2 things to keep in mind:
1) Banks make mistakes all the time, and almost never admit it.
2) Just because someone is an attorney, doesn't mean they're good at their job.
Good luck with your situation