Help with Iceline chest freezer, Urgent issue

Hello, thank you in advance to anyone who may be able to assist me,
I have purchased a secondhand Iceline chest freezer and thought everything was ok, but when I installed it, I put it on fast freeze to help it on and forgot to turn it off until I got an electric bill 8 weeks later then I realised what id done, because I keep the freezer in a cupboard I wasn’t really aware of the sound of the motor running..

after realising what I had done I turned off the fast freeze and left the manual dial midway between the letter N and Max, 3 months on and another extorionate electric bill, I went to look at the freezer again and the temperature guage reads -40

I have looked at the dial on the front of the freezer and it has various settings, min at the bottom left, then at around 11 oclock there is a symbol that looks like a circle with a line through and a letter E, then at 12 oclock there is the letter N and then at bottom right it says Max, the dial has an arrow to point it at one of the settings, obviously I understand what min and max mean but what are the other symbols and where should it be best left?

I cannot see the model number of the freezer as its against a wall and I cannot move it

I have taken a picture of the dial if there is a way I can upload it as I guess my description is not that clever

Please can someone help as its full of goods that I really don’t want to lose