Amex Credit Card Complaint

Amex Credit card department,

APR or interest rate California

I set my credit card to pay via ACH for the - cycle of 2015. Per the vendor, the amount posted of $6200.00 was declined by my bank. Per my bank, no amount was ever posted against my bank account. Regardless, after getting an email from the vendor, I paid the full amount outstanding on the account as of - -, 2015, $7700.00. The vendor continued to charge me interest for the next - months on purchases that were made after the - of - - the date on which I had a - balance. I 've called the vendor to complain and was told that the interest was for residual interest. '' I explained that I understand the concept of residual interest but that because my balance was at -, there ca n't be any interest on a - balance. I spoke with - other icustomer representatives and Interest in the amount of $210.00 that the vendor asserted I owed in the - statement was verbally credited back to my by a customer representative and I was told that I would see a credit on my account in the next - days. However, the vendor asserted that even though my balance had been paid down to -, I am still liable for a total of $190.00. The maximum amount that was outstanding for the ten day period was $7700.00, the total amount due on my account on the - of -, per the vendor. $190.00 for ten days of a balance at a maximum of $7700.00 is nearly 100 % interest. Per the 15 % stated by the vendor, I should owe approximately $31.00. I have closed this account with the vendor. I have contacted the vendor on - separate occasions about this issue.