First Niagara Bank Does not know how to properly close an account Orchard Park, New York

I switched my bank account from HSBC to Western New York Federal Credit Union on May 21, 2012, and the bank was in transition to First Niagara at this point.  I left the account open till all outstanding checks cleared and switched my accounts that I paid online to the credit union.  After reporting the correct bank account to pull money from, I had both bank accounts charged from 2 companies, which resulted in overdraft fees.   This was after my account with HSBC/First Niagara was supposed to have been closed.  How can you be overdrawn on a closed account?

I am linked to my son's bank account because he is in the service.  He left 35 cents in his account to keep it open while in the service.  They charged his account to the tune of $376.00 for a mixup due to Chase Credit taking money mistakenly out of both accounts twice.  First Niagara blames Chase and Chase blames First Niagara.   Somehow, HSBC sold my sons account to both First Niagara and Key Bank.  How is this even possible?

I've tried to close this account multiple times, as well as close my son's account on his behalf while he is in the military. I am not sure where to turn at this point, but I should not have to pay hundreds of dollars because First Niagara cannot close an account.  First Niagara will not give me any proof in writing that the account was closed, even after visiting 2 branches and making multiple phone calls.