Packet loss and upload dbmv spikes

Hey there.

I've had this problem for a very long time now (1 year and running). throughout the day, the upstream power levels will spike up to the near 60s and cause extreme packet loss. During these periods, I cannot browse the internet, stream video, etc until the power levels settle down again. The modem itself will not reboot as these occurences are only around 15 seconds long, however they happen very frequently ( around over 50 times per day ). 

I have an Xfinity supplied XB7 modem, and I have had a tech come over to try and resolve the issue. What's strange is on the day the tech was scheduled to come, these spikes didn't happen which was odd, and the tech said everything was ok. However, around 3 days later the spikes happened again and everything returned to the way it was. Thing's i've done to try and resolve this are: making sure there are no extra splitters in my connection, and restarting my modem several times (which did not help at all) '

Now especially is this issue annoying because I need to work from home, and an internet connection that cuts out every 15 to 30 minutes is a hindrance. Someone please help.