American Express engaged in billing practices that were unfair and unpredictable, and resulted in wrongful interest charges of {$560.00} on my account since XX/XX/XXXX I attempted to contact American Express about these matters on several occasions, and was told that I would receive a call back from a supervisor in the credit department, but to date I have not. 

I use the charge type breakdown tool on American Express 's website to pay my credit card charges in an itemized fashion for easy track-back for accounting purposes later. Apparently I made a miscalculation when paying my XX/XX/XXXX credit card bill, and fell short of the total amount due by {$74.00}. But the interest charge that American Express charged me was calculated against the entire statement 's balance, not only the portion left over after I paid the rest of the bill. Given the amount of the unpaid portion of the bill, the amount of interest charged was well in excess of the stated APR, and indeed, in excess of the legal limit for most transactions in the XXXX. 

On the XX/XX/XXXX bill, AMEX showed a balance of XXXX as of XX/XX/XXXX, and payments had been received in the amount of {$7700.00}, plus credits had been applied in the amount of {$440.00}, for a remaining balance of {$74.00}. But AMEX charged me {$100.00} in interest. The remaining balance was just {$74.00}, so the interest charged was in fact 147 % of the amount remaining, not 19.24 % ( my published APR ). When I contacted AMEX to request that the interest charge be corrected or reversed, I was told that I had " forfeited '' the interest " waiver '' by failing to pay the entire month 's amount due in full, so interest would be charged against the entire month -- not just the unpaid portion. I was also told that I would henceforth be charged interest on ALL monthly statements. 

In light of this experience, I have tried to ensure that I pay down each itemized portion of my bill in full -- again, using the category-by-category tool provided by AMEX. I have multiple categories to pay down, including transportation, office supplies, meals, etc., and after attempting to submit multiple payments -- XXXX per category -- on my XX/XX/XXXX bill, I received an error message from the website, telling me that I could only submit XXXX payments per day. This was unknown to me at the time, and I am still unaware of where this policy is written on the AMEX website. It also seems unintuitive because the category-by-category tool has more than XXXX categories ; I ca n't believe I am the only person who has attempted to divide payments by category. 

I called AMEX because I was attempting to pay down my bill on the day it was due, so if I had to pay the rest of the bill the following day, I would end up late again and I was afraid of receiving an interest charge based on the entire month 's bill, not only the unpaid portion. He reiterated the XXXX-per-day policy ( I have yet to see this in writing ), and offered to get AMEX 's credit department on the phone to help me put through payments in advance of the XXXX XXXX Mountain Time payment cutoff time. Moments later he said that because XX/XX/XXXX -- the bill due date -- was a Sunday, the credit office was closed. I would be unable to submit the rest of my payments, but someone would contact me to take the rest of the payments and reverse any interest charges that were applied in light of my inability to submit the rest of the payments ( especially if that interest rate was based on the full month 's bill ). Unfortunately, no one has contacted me to date. 

( Finally : AMEX 's XXXX XXXX XXXX cutoff for payments is a source of great confusion, even for a customer that has been a customer for over a decade. It was described to me for the XXXX time by a phone agent last fall. This confusion resulted in some interest charges that I am requesting to be refunded under this complaint. )