Will it cost me money to get apple to unlock an iphone 3gs from vodafone?

I recently lost my phone and while the insurance claim was going through I bought a replacement phone expecting to get a cheque for the lost phone. Instead the insurance company sent me a new replacement handset. I decided to sell the replacement handset as I did not need it as it was surplus to requirements.

Before selling it I wanted to make sure the handset was working so I put my corporate vodafone sim card in. As I am on Tesco mobile I thought if my Vodafone sim works then it will be unlocked for any network. The phone worked so I sold it on ebay.

However, the buyer has been in touch to say it isn't working and it appears that it is now locked to the vodafone network. I have been in touch with Vodafone and they have told me on three seperate occaisons that they will supply a NUC (Network Unlocking Code) to apple but need to get authorisation from my company.

Infuriatingly, despite trying to reason with them, my company aren't willing to request this and say that vodafone will not deal with the request and I need to get it unlocked by apple?!!

Will apple charge me to unlock the phone?