what can i do when there is no resolve to this isssue

I have a credit card charge of about 179.64 not exact but close, I do have the money order stub, and amscot confirmed capital one cashing money order on march 19 2019, I noticed in june of 2019 that said charge was still on my balance with interest charges .me and my wife called to settle this dispute, we offered to send in proof of payment but they stated that it would not be needed. I later noticed that nothing was done and called again to find out what was going on with my case. they again stated that they told me and my wife that we needed to provide proof, so I sent faxes from my place of employment 3 different times and mailed a copy of payment by mail. I noticed January 2020 that it still was not taken care of and called to find out again what is going on with my account and they stated that they closed my case and that they would open another one . I am done dealing with this issue with the help center and need help to resolve since having proof isn't helping.