Got a new Technicolor modem a couple weeks ago. Since then computer thinks I live in a different zip code out east. My computer location is still set correctly, so I think it is the modem that needs to be located to me. If I am online the ads are all from out east, and when I do a search the code is always 02149 (?). My zip is 80550. I can't figure out how to change it.
You likely recently received a new / different WAN (public) IP address assignment to your connection from their DHCP server / IP address pool, and the rDNS / geolocation data that is associated with it is now incorrect for you as it previously belonged to someone else that lived in that area. Comcast shuffles blocks of IP addresses around the country all the time. ISP's don't correct this. A third party service does. Unfortunately, this is typically a *back-burner* thing to get corrected. The only thing that you can do is to report it. You can try this;
Wait for the geolocation provider to approve your request. If your request is approved, the amount of time it takes to see the correction varies by provider. The average is a month or more.
Good luck !