Using an old stereo. Help?

[big al]

Hi guys, not sure if this is in the right area, but it gets the most views.
I had my new car stereo fitted last week, and sold the original on e bay, the RNS300 I think its called,
The buyer, from Ireland says that it does not work, and that it needs the code, (which I don't know where it is) can anyone help, as he has filed a paypal dispute already, and would like him to be able to use it.
Thanks

[Edition30]

Im not too sure how it works with VW but when I had a Renault I had to ring them up and pay £10 for a code 

[candy turbo]

i think if you contact the dealers give them car reg and radio seriel no they should give it you 

[BMX]

you can download the code generator and then enter the serial number on the radio set and it generates one, if vw dont have yours on file and your code isnt in your handbook then thats what you have to do