Chase Credit Card secret interest fees after paying off balance! Internet

I've worked for many Credit Card companies.  You are not being ripped off, you are just bad at math.

Interest accrues daily.  So, for example, if you owe $100 on April 1 and send in $100 dollars, the interest keeps building until your check is received.  So even though you sent in the $100, you may owe 1 or 2 dollars in interest. 

If this debt goes unpaid, it accrues additional fees and interest.  It is in your favor to pay off the residual interest. 

Same thing happened to me. I paid off appx $860 and they actually held the payment until the day finance charges posted to my account. I have bank statements that show it but they didn't care. Hopefully you just closed the account and went elsewhere. I did.