Paid bill, was never posted to my account

On 3/28/25, I contacted Xfinity to add the MLB channel.  The person then asked if I would like to save $20.00 by paying my current bill several days early.  I paid a total of $349.99, it posted to my bank account from Xfinity.  However, the following week, Xfinity comcast said, they had NO record of this transaction.  I have all the bank information, have the texts Xfinity sent me about payment, have the person's name and phone number I talked to, but my $349.99 was never posted to my bill.  I have spoke to several Xfinity assistance and they said I was scammed.  However, the bank proves it was possted from Xfinity.  Who do I need to speak to?  Tired of getting the run around.