New TV Problems- Model Panasonic TV TX-43GX550B

I have bought new smart TV (as above) which we really like. After 3 weeks of perfect use the following has occurred. (1) Mute on High Def. (2) No channel guide info. (3) No TV prog info. (4) No teletext. (5) No subtitles. (6) On occasions unable to turn TV off with remote control.

My terrestrial aerial connection is displaying 100% quality & strength.

TV indicates I have internet connection & I am able to view All playback programmes.

I have returned TV to supplier and replaced with another new same model.

Exactly the same issues are happening with the 2nd new TV. after only 1 day of use. What is the problem?