payment

I continue to receive notices that I need to update my payment info.  I have REPEATEDLY gone to the billing and payments link and tried to update (even though the info did not need to be updated) and continue getting an error message  - "The credit card details you entered is incorrect. Please check your card details."   The information is correct, not sure why it didn't process the first time at the beginning of the month when I started to receive these messages - have checked with the bank, have funds, etc. etc....bank said they are not the issue - so not sure what is going on and cannot get anyone from homestead to respond to my e-mail replies to the notifications I am getting.  Please advise!!!!