Air conditioner not working

My name is Desther, I am Nigerian and I love Chevy, the air conditioning just stopped cooling and the mechanic told me I need to change the AC compressor, of which I did immediately, and exactly within a month is not cooling again of which I took it back to the work shop and the person told me I will need to change the evaporator. so because I do not have the funds I have to leave the car for awhile, but after some month I too the car back to change the evaporator. He changed the evaporator, and yet is not Cooling, so the person is now telling me this and that etc. Then later he said may be I will also need to change the condenser and probably the compressor again. Please I really need help because I am so confused.

I am willing to hear from you soon.

Kind regards.

Thank you!