Mystery of missing MAC

18 months ago I switched from BT to SKY broadband. However SKY connect (I'm outside their main area) was rubbish, so I decided to switch back. Feb 2009 I got my SKY MAC code ... but never got round to using it, and it expired. Time went on ... and I finally got around to changing, so I called SKY last week and they said ... we aren't your service provider, there is no MAC to issue. Sorry can't help.

BT say - you can't join, SKY own your line - get SKY to issue a new MAC code .... and the saga repeats.

Please help. Where is my MAC code ...

Thanks for any advice.
Ian

ps. I recorded the phone message to SKY - I am assured I do not owe them any money, and I can keep the black box.