The A/C on my 2008 Cadillac SRX isn't blowing cold air.

What is your question?

I received a notification on the dash that said I need to service the A/C and since it wasn't blowing cold air after receiving that message I thought I needed a recharge. The shop I took the vehicle to said the system appear to be fine and there's freon in the system. They said the issue might be with the computer not communicating properly and he wanted to take the dash apart and do more tests. That seemed pretty sketchy so I declined that service and now I'm here. Any solutions? I heard something about a Receiver and Dehydrator Replacement from one of the forums.

How long has your 2008 Cadillac SRX had this problem?

Issue has been going on for 2 months.