Kind of off topic, but that's what this is here for, right?

Maybe you guys have come across something like this before.
When I was younger and attending college I had a bank account with Bank of america, both my name and my mothers were on this account. I lived at home and pretty much let her use the account whenever she wanted. I was a good son and sometimes she needed help paying bills. I had a job as a newbie tech.
However I eventually left and flew across the country to start life over, and now I live alone in Los Angeles. I left that bank of america account to my mother and she informed me that it was closed long ago.
Point: I don't do my banking with Bank of america anymore, and have moved on to others.
Problem: I was just contacted last week, apparently Bank of america claims that I have an outstanding debt with them. $1,686.95 exactly. They say that when my account was closed there was still money owed on that account. I don't know the specifics, but I'm guessing that amount rose with time.
I just don't get why they contacted me now, many years later to finally tell me this. I just received a letter from a collection agency called FBCS Inc. and I'm being told to response within the next 30 days.
I'm planning to visit a bank of america this week to see if they have a record or some information showing what happened with this account. I don't even know if what they are doing is legal.

I can understand that if I have a debt, it needs to be paid. However noone contacted me and just let it grow until now.