Xfinity cannot return me my money for Storm Ready WiFi which I already returned

I used Xfinity for a month at a new apartment I had moved in to in August of this year. Due to a situation, I had to switch apartments and cancelled service at the old one, but I didn’t realize what this will entail for me. I decided to try out the storm ready WiFi to see if it was worth it but in the end I decided to return it. I returned it exactly 30 days later, however there was already a charge for 283$ in my account, which was crazy causd there is no way that one mojth of service can cost that much. When I asked the employee at the store, they said the refund should be processed as I returned the Storm Ready Wifi on time. Since then, I spoke with six different customer service representstives, spent countless hours with the Xfinity messaging app and have been directed to several forms to fill out. This all culminated in me getting an email that my xfi pods had their warranty expired but the product I had is not even that, it was a used storm ready WiFi. I have had no indication thay the money that Comcast took out without my permission, without giving me a warning that it will be done, without notifying me of the amount that they will take out even BEFORE the deadline for return of the Storm Ready equipment. I need this money refunded back to my account, I do not have the luxury to be out of almost 300$ as a Student. I do not want to speak again for countless hours to a customer service representative, I can submit all the proof of what I have already done, i just want my money back for something i didnt even do.