Fridge /freezer repair engineer

Hi, fridge /freezer not freezing but still working only three and half years old anyone know someone who could look at it.
Thank you

This happened to our fridge-freezer, try disconnecting the whole of the appliance for at least 4 or 5 hours then plug it back in, it worked fine afterwards, but obviously you will be without the fridge for that time, there is a tube in the freezer sections that can freeze solid, allowing only the fridge to work, that hopefully is the cause of the problem.

Will try this...thank you

Got your message Roy thank you ,we now think it's the thermostat husband has sent for one but had it off most of yesterday and all night plugged back.in ......nothing but it was worth a try.