Citibank Consumer Loan Complaint

Citibank Consumer Loan department,

Installment loan Managing the loan or lease Iowa

I took out loan thorough Best Buy c.f. for no interest if paid before - 2015. I set up payments through bill pay at my bank to insure prompt complete payment. For some reason, the last payment was short something like $0.00. I hear nothing more for 3 months until I happen to see an e-mail from Citi Bank and a bill for $160.00 and change. I call to see what the problem is and I do speak to plenty of people at the bank. They were quite gracious in reducing the bill to $120.00 and change. I now realize that there were calls on answering machine that were unintelligible, and this was probably them, but I still do n't know.