Returned modem and Moved; STILL GETTING CHARGED

I moved from my home in July 31st 2025. I canceled my service starting August. I returned my gateway to an official Xfinity store in Springfield, MA. I confirmed with the service assistant there that I had canceled my service. I saw a charge in September. I spoke to someone online through the Xfinity website. I confirmed with him that I canceled my service and he said he would return the charge. Now it is October 2025 and I have gotten charged yet again for Internet I am not using, at a location I am not living, with a Modem/Gateway that I returned to the store. And it turns out none of my money was refunded to me. The website is making it impossible to get in touch. Xfinity owes me over $369 for services that I canceled TWICE. They are making it impossible for me to cancel my services and continue to charge me. I don't trust that when they say they have canceled my services, they actually have. If this isn't rectified immediately, they will be getting reported to the BBB, as well as negative reviews and warnings over every place I have access to. It is deeply unethical to trap people into using your services (making it incredibly difficult to cancel) and continue to charge them for services that they have previously canceled TWICE--even going to a physical location to ensure that.