From Ross-Tech Wiki

4.12 Can I use VAG-COM to retrieve my Radio Code to get it out of "SAFE" mode?
No, You'll need to get the radio code from your dealer (it should also be on a card that came with your car). Most likely, the dealer will need to physically remove the radio to read its chassis number, then the chassis number is input into a database at the dealership to retrieve the radio code. Neither VAG-COM nor the factory scan tools can retrieve the radio code for you.