Slow download speeds after cable was replaced and buried

The cable crew came out and buried my cable after about 2 months since it was hooked up. I was getting about 200 Mbps download speeds up until the day before they buried my cable. Now I am getting between 50 and 90 down. I get over 200 down using my cell phone as a hot spot. This is RIDICULOUS!

I called and spoke with a customer service person who went through a series of worthless checks and system tests only to blame the speed issue on my modem and laptop. I have not had any issues with my modem. This is not a modem issue. I have seen other posts with similar download speed issues. 

Unfortunately, I just signed up for Xfinity TV with my internet and I am locked in for a year now. UGH! My previous provider warned me about this, but I thought they were trying to convince me to stay with them using fear.

This has to get resolved!