@louboo We are customers like you on here. You will need to ring Sky about this. Flickering picture does not sound like an internet issue to me, though freezing might have been.
Do you know what speed you are getting to the TV from your internet provider? Is there a lot of devices using the internet at once?
If your TV is less than two years old it is covered under warranty. Don't let Sky fob you off. Tell them you want it replacing as per the warranty if you feel you have a faulty TV.
Having said that, there is a known firmware issue at the moment that we are awaiting Sky to fix, which affects the TV by causing a black screen with sound and taking ages to connect to a programme. Does that sound anything like your error? I only mention it because Sky are aware of it and may mention it when you ring them. It can be temporarily fixed by signing out of the Prime Video app and doing a TV restart via the settings (not a factory reset though).
Beyond that, how are you connected to Glass? Is it via WiFi or Ethernet? Ethernet cable does give a more stable connection than WiFi. If you are connected this way make sure WiFi is turned off in the Settings.
