Finance charge even when credit card paid in full?

I sent an email to *** asking for a breakdown on the finance charge that I get charged on my credit card because I pay my card in full at the end of each month. Today is the 28th and I am yet to receive a reply to my mail. The one email I received on the 18th stated that there was an outstanding balance from the previous month, which is untrue. I think closing this credit card account seems to be the best option at this stage!