is there any sort of warranty if lets say hbo go stops etc.
I have had one of these in the past and alot stopped working and
I wasnt sure how to get them back and didnt have user names
and passwords to get the channels
HBO GO is not gonna work for you unless you have a subscription. But for the most part anything you can find on HBO Go can be found on other apps that would be included. Their are probably like 20+ apps that would let you go shows and movies exclusive to HBO and in HD quality. HBO lie is tougher to find and the quality is never perfect but it cna be found in multiple apps as well.
If the app stops working, most likely an update is in order. I have given you a third party app store which can perform updates on multiple apps at once so you keep it up to date that way.