System error

Was sent 8 days post my monthly payment already paid manually and thought well Manet I forgot so I went ahead and paid what they said was due   I am not nor was not behind   A fixed income and can’t afford to give any bills due an extra payment.  When I checked my balance on card I thought should been more that’s when I scrolled down transactions and found the 2 payments maid to Xfinity and cslled 3 x in which I was told it should be back in my account card I used in 24 hrs.   24 hrs later I CSLL again now I see a credit on Xfinity for next month and some towards the following .. I told last s agents I talked to I didn’t want a credit and that I thought I was doing right by paying when requested for 2 nd payment that was already paid and cleared now they say call   Direct express and they will credit my account but to my understanding they will have to dispute it and I shouldn’t have to go through all that when they can clearly see I’m sure the email that was requested to make payment due which is on 8th but I paid it on the 2 nd of July .. to me that’s a fraudulent move on there part when 14.95 is not a big ant it’s very big to me when in set income