Capital One Credit Card Complaint

Capital One Credit card department,

Payoff process Ohio

My wife has a Capital One Platinum card. $5000.00 credit. She quit using the card in -, after she retired. The last time she used was for a dental appointment which almost maxed it out. Since late - we have been paying on it monthly with out fail between $120.00 to as much as $200.00. All of this time the principal was creeping up by a few cents. As of - - - we have paid $12000.00 on the bill and the balance had come up to less then $500.00. I finally realized that that did not look right and contacted Capital One and was given the story about interest verses balance. But when I pointed out that we were not using the card they said it made no difference and ended it there, but the balance did jump from under $500.00 to $890.00, still far less then the almost $13000.00 we paid out.