Sling TV complaint: Billed for services not received

On January 3, 2021 I tried sling for an hour at most and then canceled the service. I replied to several emails and typed cancel service and I canceled on the website after logging in. On February 2nd while paying my bills I saw that sling had charged me $49.83 on 172021. The next business day I called and explained what had occurred and the representative would not refund me but she said she would cancel my service and assured me I would no longer be billed. I was very angry because I’m tired of being taken advantage of by big business and had a 38 minute discussion about this. She told me Sling was would only allow her to refund 30 days back. January 3rd to February 3rd is 31 days. I also canceled again on line. On 282021 I opened my account to check something for my husband and find that sling has charged me again. I called sling and the representative. Of course the representative tries to find a way to get out of refunding me stating, that if I did not receive a cancelation email on February 3rd I did not cancel properly. I explained to him and to the supervisor I asked to talk to that I was not told by the 1st rep or on the website I needed to see an email to cancelation. I also explained to the supervisor who assured me I was canceled now and would receive a refund for February but not January, how do I know that is true since I had canceled twice before, was still charged by sling and then refused a refund. She told me i couldn’t talk to anyone higher up then her and to go back to the sling.com website to file a dispute and resolution. There is no such thing on the web page. No way to complain or dispute.