How can I speak to a supervisor? Absolutely frustrated with customer service reps making unfulfilled promises to send upgraded equipment!

We have been having longstanding issues with our internet and TV services. I have reached out to Xfinity 4 times (1/6/26 through chat, 1/18, 1/25, 1/29 through phone) and spent 3 hours of my time with promises being made by your reps, only for them to be unfulfilled. We have requested to have new/upgraded equipment (WiFi Gateway and 3 TV boxes and remotes) sent to us as we have had the same equipment for about 8 years and have been having issues with WiFi dropping or not reaching parts of the house that it used to reach. TV services have been freezing/glitching, looping, cutting in and out, and changing to a different language without input on our part. We have restarted, refreshed, and pulled power—sometimes this helps, and if it does, it's just temporary. We end up having the same problems over and over. It has been frustrating. Your reps also agreed and recommended updated equipment to us (upgrade from XB7 to XB8) since we have had the same equipment for so long.
We have been sent an email, given confirmation numbers and ticket numbers (which I could provide, if needed) by your reps for new equipment to be shipped to us. The closest Xfinity store is close to an hour away, so that is not an option. We were told we could get a shipping label from Xfinity and go to UPS to ship our old equipment back. We will be going on a month since the initial request in a couple of days. Each promise made by each rep went unfulfilled and asking to speak to a supervisor went nowhere as the rep said they were able to do what a supervisor could do.
Please help with this request. It would be greatly appreciated.