My mortgage was Sold to BOA without my knowledge, can I object and ask for another bank?

On Sept 4th I recieved a letter from BOA they now had my mortgage as of Sept 1st. and that payments due after August 11th should be mailed to them. I did not recieve above letter in time and had already paid Sept. payment to TBW(Old lender). Well apparently TBW went bankrupt and kept my Aug. and Sept payment and never sent it to BOA. I have copies of cashed checks from them. I started getting collection letters and calls the next week. I have been on the phone with them for many hours to no resolve. I have offered to send them my copies of cashed checks but they do not want them. Told me they would report me to credit entities, late fees, so on and so forth. AHHHH! I even had my bank(Wells Fargo :) ) who my checking is thru do a confrence call with all of us to prove it. Nope! Not resolved. This sounds illegal to me. Doesn't FDIC mean I am protected?Oh, by the way I have really good credit, never missed or late on a payment, always pay extra, don't have credit card balances. I just don't understand, why are they trying to ruin my credit. I just don't want to be with them, can I change? Is this illegal what they are doing? Who do I contact? This is Hell!