I'm sorry to hear about this. May I ask for about how long this problem has been going on? Also, which firmware version is the TV currently on? The current version is 1105.7.
When using video streaming apps like Amazon Prime, or Netflix I noticed that my streaming is very slow. Watching a movie it cuts to the load screen about every 5-10 minutes.
I am subscribed to a 12mbps down service that is often clocked in at around 18 mbps via speedtest.net
I checked speed while the load screen was on the TV screen and throughout normal playback via my computer which is connected through wifi and it showed speeds well over my 12mbps
The TV is currently set up via wired network.