Servis Fridge Freezer Lights On and Off?

Green light (Power) and inside light (if door open) have started to go on and off randomly and motor stops - as if there was a power cut. After lights back on, if I try to restart the motor by turning the thermostat to the maximum setting, it just make a strange noise (like it tries), but won't start. If left alone, after a while it starts working but motor goes on for about 50-60 mins (eating a lot of electricity I assume). I checked the plug and the socket but they are ok. Please help! Many thanks!