Cox credit card "returned payment fee"

Paid my bill online through Coc website like I always do with me credit card which is stored in the payment section. Got email seconds later saying "Thanks for your payment, payment has been submitted." Then 24 hrs later get second email saying "payment not successful" click here to pay bill. Did and paid the exact same way I did yesterday. Then notice $25 "returned payment fee" on account. I call customer service and get the ruddest person ever who tells me that the number that was entered was wrong so it could not be processed so I get charged $25 fee. I tell her and the "supervisor" Zach (which is probably the person in the next cubicle and not any type of supervisor) that Cox's website told me the payment was submitted successful and even sent me an email. If number was incorrect or any other issue I would have been told credit card invalid. I asked what was the number and thy cant tell me because all they can see is the last 4. Then how can you tell me the number was wrong?! I  I have been using the same credit card for months paying online, The last 4 of last month was the same as this month, cox said the payment has been submitted but still will charge you $25 even if they cant tell you the number that was entered. What a scam. If you enter the wrong CC # wi Cox Cable they will accept it then tell you later it was was unsuccessful and you owe us $25 dollars! Never have I experienced this in all my life and I'm old.