997-c2

Hello all
New to the forum and love all the info I can get from reading.
Just bought my first Porsche it is a 2007 997 C2. The day I made the purchase was a cold day in Texas and did not check the A/C, few days later was in 80's but I got warm air so I took it to a shop to have it checked for low freon, after the guy ran a test he told me all was great but no power to compressor, he called a dealer and was told to check fo bad relay and there it was he took the top off and with the screw driver activated it and ther came the very cold air, he told me to go to autozone and pick one so I did he installed it and turned on the ignition and there it went my controll panel puff blank...we left it at that and took the car to independent Porsche shop, they cleared all errors on computer but could not read the controll unit. I was told to buy a used one I did from ebay day after I called a dealer and I was told no other than new one will work since it had to have the new software installd $2000 is what is asked.
Is this a correct statement?
Thx in advance for all your help
Ben