updating my payment information

I was notified by email that my credit card automatic payment did not go through.  I went into my account and attempted to update my payment information.  3 different cards I submitted were declined.  All of them work every where else I use them and are all current.  I believe something is wrong with your system not on my end.  I have tried to find a phone number so I can  call to fix this error but I cannot find a phone number to call anyone which is the main problem with DirectTV.  computers sometimes have glitches and with No live people to help, don't know how to remedy the problem. I am trying to pay my bill and your system won't accept it.