I called 18888564255 to pay my citi hhonors card, the rep said it was not possible with debit card. Called a number on the citi site and the rep tried to pay my balance of ~2100 and it failed, I asked her to try with 900 and it failed. This was with my paypal debit mastercard. I was trying to pay the balance before the statement close, so not sure if that is the problem or maybe its my paypal mc?