Citibank Credit Card Complaint

Citibank Credit card department,

Late fee North Carolina

Went online to my bank to pay bill 2 days before it was due. The next day was grayed-out on Citibank 's Bill Pay and would not accept payment, which was not the case with other bills I was paying at the same time. They were open to receive payments the following day. I called my bank and they said it must be a problem on Citibank 's end. I paid, assuming that they have a grace period like other credit cards when the due date is on a weekend. The payment reached them on Monday and I was charged a late fee. I called them and asked that it be forgiven as a one-time courtesy, as I have never missed a payment and have always paid in full, which is also this case with this payment. They refused to remove the late fee.They charged 14 % interest for 2 day late fee which works out to roughly 2,500 % annualized