How can I fix my hotpoint mistral plus frost free fridge/freezer?

Hotpoint mistral plus frost free fridge freezer.
Can't find the guide book.
The window at top is flashing FF and looks like a thermomator is flashing at right hand side. At left hand side looks like a picture of the fridge freezer a little coloured in black at the bottom and an arrow pointing/flashing at it.
The ice lollies have melted and the stuff in the fridge isn't very cold.
Any suggestions what to do please? Thanks.