I have this exact same problem every summer (SE Michigan). The hotter it gets, the more frequently the service drops. A modem reboot usually fixes it, but it could drop again in ten minutes or maybe it's good for an hour. TV is less affected, but sometimes it'll go, too. I get the same run around about cables and splitters and hardware and yadda yadda but my brother is an Xfinity tech for 14 years and did all that himself. The only thing that fixes it is September. It's infuriating.
