PAYING for 1000 mbps and gettin 8 mbps ....Internet was fine in Sept and getting 947 mbps hard wired

Hey guys I need help with this issue

I moved into a new home and was getting 947 mbps from september 15th all throughout the end of the month.

However, my internet dropped drastically in October to 35-40 mbps and then now to 8-18 mbps

My setup intially in september which received the 947 mbp hard wire and 500-600 mbps through router ---> Netgear 4200x Orbi Mesh system paired with a Netgear CM1100 Modem

I have called the tech people. Saturday a tech came and he just changed the heads of the wire, one from inside my home and the other from the outside main box. He said his device was saying the numbers looks fiine but he could not tell me the exact download speed according to him. Which i later found out was not true because the tech on sunday was able to tell me speeds his device was reading. The Saturday tech only started working 6 months ago ...btw but my laptop hardwired was giving out 35mbps which i showed him.

He called his supervisor since he was a contract guy and then called in for a line test on sunday.

On sunday the line test guy was supposed to come between 3-5 but was running late so i guess they sent a new guy who showed up at 530pm. 

The day before i had SPECIFICALLY requested they bring a comcast xfinity modem so i can show them the modem is not the issue.

Anyways he looked at the wiring and saw that the connection was loose wherever the other tech put one in and he fixed both the main box side and from inside my house. He showed me 1100 mbps on the main box side with his device plugged in and us reading it on the app on his phone. He also showed me 847 mbps first from inside the home but when he ran it again it was coming up as 1080 mbps on his phone app for the device.

So here I am thinking everything is fine... I hard wire my laptop and its showing 25 mbps... he said for me to go get the xfinity modem and everything should be fine.

Well he should have brought the xfinity modem as i requested.

BUT ANYWAYS on Mmonday Nov 2, 2020 i went out and picked up an Arris SB8200, a Netgear CM100 AND ALSO the brand new xfinity modem.

I had them provision the cm1000 first and I got 20 mbps

I then said forget this and told them to provision the xfinity modem and the tech was so shocked that she was seeing 8mbps FROM HER END!

Now they know it is not the equipments fault as their own modem router is getting 8 mbps for me.

Now another guy is coming on thursday and this is getting crazy because its impacting my work from home capabilities.

I have so many connection drops throughout the day. I have not seen the T3 T4 error on my log but i am seeing MILLIONS of codes and correctable and uncorrectables on the down stream side.

The upstream seems a little high at 51.8, 50 and then a few 49 and 48s

I will attach the pics here and hopefully mod approves them soon so you guys can advise me what to do,

By the way i live in a town home and all these wires are run UNDERGROUND for every single house so how would the tech even run a new line for me?

Anyone know how this can get resolved? I read other places they have to find the bad amp but where would that be?