unless you are well versed in working on a hermetically sealed refrigeration system, and if you are asking on here you are not, you as a consumer should never even consider doing anything to the hermetically sealed refrigeration system. I can only hope that you have not compromised the system, and have not allowed any ambient air, including the moisture it contains, into the system, and thereby making the entire unit useless. Adding refrigerant to a refrigeration appliance is VASTLY different than adding freon to the car A/C unit, which can and does lose refrigerant.

If the compressor is really cold, chances are the compressor is not running, that, and not low refrigerant level, is your problem. could be the compressor or the start kit. But if you have opened up the system, it wont matter.

But I fear that you may have just bought yourself a new refrigerator sir.