Liebherr Fridge Freezer fault

Good evening people, please excuse my ignorance and lack of knowledge.
The freezer section of my 4yr old Liebherr KGNv 3646 Fridge/Freezer has stopped freezing. The fridge is fine, maitains temp of 5, but the freezer temp is fluctuating between -5 and -10 instead of the usual -18.
The black drum thing ( compressor? ) is hot, but one of the small pipes coming out of it has got so hot it has melted a rubber gasket type thing where a couple of smaller pipes pop out, above this the pipe is cool.
Any tips or suggestions would be greatly appreciated.

Try defrosting the freezer section overnight (a good 24 hours would help). Switch it back on and retest it.

Chillin:):)

Thanks I'll try that

Clean back of the fridge from dust and debris with brush, than see temperatures.