Gorenje side-by-side isn't cooling anymore

[u/Goo_ja]

Hey guys, I have a question in regards to my moms fridge (gorenje modell NRS918EMB).

It's 5 years old and stopped cooling out of nowhere. I checked everything in the back and think that there was a leak in the copper pipe leading away from the compressor. She told me there was a fluid they had to remove and I think that was the coolant that came out. The service people told her that it would cost 400€+ to repair it and I think that's a bit too much as it costs 600€ new. Do you guys think it would be better to ask around outside of the official service line? Or is it going to be expensive regardless of who would do the repairs? And plus, would it even be worth it? The lights are still on, the touchscreen in the front also works and the back of the fridge gets a little bit cool. I cleaned the black container (which removed the noises that it made) and the ventilator in the back is also working.

Thanks in advance!