FF200E Hotpoint Fridge not cooling?

Hi - I left the door open on my Hotpoint fridge (ff200e model) accidentally for nine hours and now it wont work. I have turned the fridge on and off at the mains, but the fridge is not cooling. The freezer door was closed at all times as is working fine. I have pressed the various buttons at the top of the fridge in an attempt to get it to work with still no luck. As you can gather I'm not the most technical person, so some advice one how to resolve this issue (without having to purchase a new fridge) would be most appreciated. Thanks You in advance with your help on this. L :oS