Capital One keeps charging customer late fee for on-time payments: Money Matters

I'm having a terribly annoying problem with my Capital One credit card account. For four of the last seven months, I've made my payment on time -- as I always do -- but have been charged a $25 late fee. My online account shows the payment, and shows the late fee on the same day. Then, a reversal of the late fee shows up a few days later, without my asking about it.