FM09 De-activation

I have just purchased FM2010. This has made my FM09 surplus to requirements. My original intention was to use it to sell in CEX or part-exchange in Gamestation for FM2010. Unfortunately no-one will take it as I have activated the key-code.

Cash Converters have agreed to take if I can prove that it is not active.

I went on to the De-activation site to clear the active computer but it wont work. It says that it is unable to de-activate. I know you can have 10 pcs active on the code but they wont take if it is active on any.

Can anyone help me with this. (Unless anyone wants to but the game from me).

Thanks