Fluctuating QOS / Low speed

Team, 

I've been struggling for a few weeks now trying to get my service restored and can use your help deciphering these CM2000 logs.    In short - I pay for gig service but I'm only getting 70mbps hardwired.   There are days where I see 1100mpbs when all is working but then it tanks.  This has been going on for a few weeks now.   Any help is greatly apprecaited!     -Jim

These logs were taken today when things are "bad" - 

CM2000 Overview - High "Uncorrectables" count

CM2000 Error Log  - Constant flow of "MDD message timeouts" every 1-2 mins

Speed Test History  -  Shows the fluctuating QOS

Prior to buying the CM2000 I had (2) XB7s that also had the same issue in terms of speed fluctuating.   I've had 2 techs at the house in the last week and now I'm waiting on a call from corporate.  My goal here to try and understand the logs so I can help point them in the right direction.    So far I've had (2) new drops into the house going directly into the cable modem.   One bypassed the ground block just for testing purposes.   The last tech worked on the tap and when he left I was seeing 950mbps wired just to have it drop again the next day.   It feels like the cable modem is loosing sync (provisioning?).   I say that because when theres an issue the modem will show as not connected via. Xfinity app and I feel like a reboot gets it going for a short period of time before it falls out again.     All I can do is compare logs from previous snapshots and one thing that stands out is the "Acquire Downsteam Channel" - its showing 405000000 and before it was 507000000...  Also, the upsteam has always been 100%.    I'm not sure what else I can do...  

Again, thank you in advance for taking the time to read this and provide any feedback!  

Much apprecaited, 

-Jim