Why do you need card details when a refund would be due?

[#1]

On the ticket with my Mac Code it states I need to provide details of credit/debit card for further charges to be claimed.  However as I have just paid for the month and will be migrating hopefully after 2 weeks I should get a refund.  When I spoke to Customer Options they said I needed to keep direct debit active until refund made. On phone no mention was made of a card payment.  So why do PN also need card details? 
This seems a little over done - surely they check what your situation is?

[#2]

Hi Josie,
Obviously I can't comment on your specific situation - but I can share my suspicions.
You may have received a 'stock ticket' which is designed to be a belt and braces approach - containing all the information that would be needed for most situations where a MAC is requested.
The agent may have just overlooked a short paragraph/sentence that they ought to have removed. (A recent MAC request I received was similar - with a note telling me I owed "£      " and should ensure valid card details are present so they could charge me that. :?
Doubtless a DC Bod can confirm it to you - my money is that it is a mistake and is safe to ignore.

[#3]

Hi Josie,
If your Direct Debit is still active, then we would refund against that, if we were refunding a payment that was taken from your DD.
If however, you had made a one off payment by card, which we would be part refunding, we'd need to do it against that card as we'd only refund against the same means of which the payment was taken.

[#4]

James G - rather suspected that
Jamesh - thank you -  as always helpful - at least by putting this query in the Forum you get a quicker reply than what you get to ticket!!  So I assume that I do not need to give you my card details now.

[#5]

I've just taken a look at your account and we won't need card details. We have your Direct Debit on file and there are no cancellation fees (e.g. a rotuer or house move fee) that would require one-off charges to be made.
It's likely that there will be a small refund so please leave your Direct Debit active.

[#6]

Thabk you Ben.  The refund will need to be adjusted I am sure as the dd will stay in place as I want to keep up the basic email that is £1.69 per month [informed that will keep my domain name going too] and I already knew that there would be no other charges.