Intermittent Issues for over a year

Ever since moving to my apartment complex over a year ago have had intermittent, but severe connectivity issues, from 1100-1300 daily, and during peak usage times. A tech game out last year and fixed/replaced some connections, and left his "supervisor's phone number, in case issues come back." They did, and the phone number's voicemail was full, and never responded to multiple phone calls. Recently got new modem/router trying to fix issues, they didn't. I now have modem logs from my netgear CM2000, showing upstream issues on xfinity's side/equipment demonstrating multiple upstream ranging failures implying plant problem/T3 timeouts. I would like to please talk to tier 3/advanced technical support/network engineering team to resolve the problem(s.)