Tvapp-00500 error code

I was on the phone with support for OVER and hour.  And they could not figure out why my xfinity stream, which I've had for 8 months, was not working.  After numerous failed attempts they told me to give them another hour so thru could run diagnostics.  They then sent me a text and said everything should be working fine now.  NOPE.  Still  not working.  They even had me delete the xfinity stream app, re-install and still.not working.  It's giving me the error code TVAPP-00500  

This has been an ongoing issue and it's unacceptable at this point.  

I pay for the "fastest" internet and the internet barely works in my house.  I harely get wifi anywhere in my home.  I have been complaining about slow wifi for years and now during the diagnostic they say they see there matly ne a connectivity issue with my modem.  

This is ridiculous and I've been lied to for years now.