TV won't boot

Been on and off for a while now. There are a couple of issues. When it was booting there were vertical lines on the left side of the screen as you are looking at it plus in the lower corner on that side a weird pale blob. I can actually live with that until I can afford to replace it.

When I switch it on, even after a week or so off and unplugged the screen sort of paley lights up and you get the hello sound and this last time about a second of audio but nothing else. If its left on you get an occasional repeat of the hello note and the screen paley lights up but no picture.

Its in warranty but Samsung won't touch it, they asked for a video and said it was damaged - it has not been damaged but they won't budge.

Going backwards, this is about a month of not working, prior to that there were about 3 weeks when it did work (with the screen issues still there) that was actually a spontaneous awakening it happened to be on, wasn't working then decided it would for a while. It didn't work for a month before then but just before that it was sort of working but was actually switching itself on over night and was a bit flakey when I actually wanted to watch it

Jiggling the network cable that connects it to the modem sometimes brought it back to life a few weeks ago. I have changed the network cable and the extension lead it was plugged into already.