xfinity set top boxes repeatedly failing for past 2 months

Hello. About 2 months ago the set top box i had for a long time died and had to be replaced.

Since then I have had about 6 replacement boxes and each one has the same new problem: the tv will turn on but the set top box becomes frozen and unresponsive. 

A couple weeks ago comcast finally decided to send a tech - the tech confirmed cabling is perfect up to the box and the box would need to be replaced again. 

He installed a brand new box and it had the same problem - quickly becomes unresponsive and freezes. 

So he tried an OLDER model box (larger style with clock on front) and it worked. 

For the last 2 weeks i had been using this older box - but the guide is slow and loading apps like netflix etc are extremely slow compared to the newer models, and also I wanted multiview. I took the box to the comcast store and traded it for the small newer model wifi box.

New box installed yesterday and worked until today - when it too became unresponsive. 
Using xfinity assistant to remotely troubleshoot and send refresh signal the box was fixed for several hours - then an hour ago it once again became unresponsive.

I power cycled it and it is working again.

There is something being missed on the account causing these boxes to become unresponsive. For over 2 months I have spent countless hours with the xfinity automated assistant, on phone calls with xfinity support, and at the xfinity store numerous times to trade these boxes out. 

I really need this issue escalated to a higher level of technical support to dig deeper into the root cause.

I have been paying FULL PRICE for extremely poor quality service and not been refunded for the non-stop issues for over 2 months. 

Please help to resolve the issue.