"The lines appear only when watching tv through the blu ray or when playing a console using composite cables."
Well composite video is only 480 lines so there may be some TVs that are big enough that will show lines.
However if the BD player is connected with HDMI and shows lines, try unplugging all other inputs as well as another HDMI cable for a test. Tell the forum what you find.
I've got a samsung LA32R81BD plasma tv which is quite old now and only recently there have been tracking lines appearing through the picture when watching tv through the blu ray player (model BD-D8500A).
I've been using the blu ray player like this since we got it and haven't had a problem. This only appeared about 1 month after having foxtel installed.
The lines appear only when watching tv through the blu ray or when playing a console using composite cables. There is no problem with the picture when watching Foxtel or playing a console using a hdmi cable.
I'm not entirely sure what the problem originates from but I'm starting to think it may be caused by the foxtel box as the picture was fine before then.
There's also a dark spot in the middle of the tv, and it is having burn in problems. A lot of the time the lines will stay on the screen if a scene is paused etc. it is a bit annoying but tolerable. Sometimes it is worse when playing a game with high contrast colours, Red Dead Redemption is the worst for burn in.