GIG Internet running at 50MB or lower after tech was out on Sunday to work on downstairs apartments issue

I'm paying for the 1.2GB and a tech was out on Sunday to fix the downstairs apartment...low and behold later that night, 1/19/25, my internet starts acting crazy and speeds went down to 20MB but upload speeds went up by 10...go figure. I call xfinity and the earliest they can get a tech out is this Saturday, 1/25/25, so I have basically been out for almost a week, gotten 2 calls trying to do internal troubleshooting plus a couple of text saying the network is fine but the last tech that called today even did testing and was shocked I was getting less than 1% of the speed I pay for and, like most people, I work from home at least a couple days a week. I have a feeling if they have to replace the line, it will probably be another few weeks as this is an apartment complex and they would have to go into the attic. Waiting a week to get a problem corrected that they caused is crazy to me. I did log into the modem and the only channels I see are 12 and 7 for downstream and 1 for upstream. SNR is 26-31 dB and power levels are -23.4 dBmV which seems way off