My fridge freezer keeps cutting out?

Have a Bosch KGV range. Fridge on top freezer below. It recently defrosted itself whilst was away for few days. Came back and had to empty out the contents, clean/mop up etc.

Now the machine works and then cuts out and when check it is warm inside again. Then swith off at the main switch and it kicks in and compressor fires up.

However it keeps then working short while sometimes hours or days then cuts out again and warm inside. Then have to switch off and on and then starts up again.

Any ideas what is going on and how to cure it? As VAT about to increase wonder if need to get a new fridge freezer otherwise prices will increase and also my food will be wasted and go off.

Help please anyone.