Illegal draft from my account

I received a letter from TRS Recovery stating that they had received a check I had written that had come back for insufficient funds.  The check cleared the second time it was presented but TRS then WITHOUT MY CONSENT helped themselves to $50.00 saying that their sending me the letter stating I had the outstanding balance constituted consent for them to draft this $50.  It does not!  When I called them and asked what they were calling consent they couldn't answer the question but said "I'm sorry for the inconvenience, but that's how we operate."  So I see by the volume of complaints here.