From: Holly_Vodafone on
Hi,
I'm with Vodafone's Web Relations Team but I imagine the process is
still the same.

Its true you can have both a PAC and give 30 days notice. If you give
30 days notice then your account would terminate at midnight on the
30th day and your number would be recycled. If you use your PAC
however the number goes to another provider and as soon as the other
network has your number then your previous account is cancelled, as T-
mobile no longer have your line and so cant charge you line rental. If
you request your PAC and don't use it the PAC will expire and become
invalid and your T-mobile contract would run as normal.

The only thing I can think of is that you requested your PAC code
before the end of the contract, and if used T-mobile would bill you
any remaining line rental on your account, so if you transfer your
number 2 months early and your monthly rental is £20, you would be
billed £40.

I can't guarantee T-Mobile polices are exactly the same but it would
explain why they wouldn't let you do both.

Hope this helps

Holly
Web Relations Team
Vodafone UK