DVR download via Xfinity streaming app on Iphone video freezing

This has been posted multiple times and am looking for a reply from Xfinity rep that actually solves the issue.  Please don't reply to reboot phone or to delete and reinstall app...that solves nothing. 

Sick and tired of paying the monthly bill (way too $$$$ for the service or lack thereof) to have any issues (and I don't pay what others do), but because I am not on an unlimited mobile plan (also with Xfinity), I download shows using the streaming app to watch them on my phone when not at home to avoid going over my mobile plan limit. 

Has happened before, but haven't had any issues recently, but now the issue is back:  video freezes, but audio continues.  Sometime happens a minute or two in, other times it doesn't happen until later and yet other times - doesn't happen at all.  Inconsistency is Xfinity's middle name.  The only thing that has changed recently with my phone is I had it on airplane mode when flying.  Videos froze on the plane and they're doing it again now that I'm back on land and off airplane mode.  Only solve I've found is to return the download and watch using Wifi (not always available especially when on a plane, in the car (someone else driving) etc.).  Doing this defeats the purpose of downloading.    

For the price that is charged, I should be able to do something as simple as watch my DVR on my phone.  If the downloads don't work, then stop offering it.

Also, why am I having to re sign in every few times (again not everytime so there's that inconsistency middle name again) of accessing the streaming app?  Never had to before - signed in once and good to go.  They only thing I can figure is I'm sometimes on a different Wifi network (work vs. home).  Any setting that resolve this?