No No No !

well water being one of the fluids that actually expends during freezing it depends how much expansion room there was in the tank and how flexible it is. The drain pipes are rubber plastic but the tank might have broken? It might be an idea to be there as it defrosts (speed it up perhaps) to catch any spillage rather than go back in a few days to find a very wet mess everywhere? 

Have you contacted your dealer and/or toilet manufacture for advice? 

Put some warm water in it to melt it, then refill and check for leaks.

Chances are it will be fine.....lots of expansion room in a tank.

Its not so much the tank that goes, its the plastic body on the pump that's the weakest point. If it has its an easy enough job from inside the cassette cupboard, a mirror comes in handy to look up at the pump, no screws just a couple of clips...

Phew , panick over , there was a little water in the tank and a little ice in the loo flush pipe , put a little hot water in the tank , warmed bathroom after an hour all worked ok , and no leaks .

Thanks for suggestions .

Saw this over on Swift talk, glad you are sorted.