Vintech wine cooler

I hope you can help!
I inherited a dual zone wine cooler. It would run continuously so I assumed low on gas. Had a fridgie mate recharge the system. All seemed well but then I found the compressor not cutting out. Suspected the main control board. Mate supplied same. I now discover the lower zone is not cooling it is warm to the touch. There are 3 lines on the compressor two are cool but one is hot and this goes to or from the condensor. Any insight as to what could be the problem before I annoy my Mate again.
Thanks