I have got 1 from Argos before in the UK. It was a green 1 and it came with a Mametchi character figure. It is the Mametchi jumping/happy pose. Hope this helps!
I think that is is either the battery's or the temperature changes. It is probably the temperature changes but change the battery's as well just in-case it is them. Hope you figure it out and get it mended soon!
I have never tried or heard of it before but I think that they are trying to copy Tamagotchi because of the planet on the top right looks very familier to me. (Tamagotchi Planet!)