the relay is timing out this was caused by over run try turning off for 1 hr to let it settle and decompress if it does the same fit a new relay and try if that does not work it meens the compressor has gone expensive repair
I take it this is a manual defrost unit. So, unplug unit ,get a tray of warm water, put in freezer, leave door open , get some towels allow ice to melt (2 hours or more) mop up , restart unit. you can speed things up with heat gun but be careful not to melt any plastic. Use no sharp objects!