My WB hell - sensible advice needed!

[Hannah]

Hi everyone!  

I know you're all a sensible lot (well, most of you, anyway!!), so I 
could really do with some advice.  I pre-booked my ticket to see 
Harry Potter through the site for Warner Brothers Cinemas, 
Inverness.  It told me that I would be able to cancel or change my 
booking, but didn't provide a link to that option.  That didn't 
bother me at the time, so I went on and booked, using my mother's 
credit card (with her permission, naturally), as I'm only 17 so can't 
have my own.  So I book it, and that's fine.  Then afterwards, it 
gives me a message saying "Please bring your credit card to the 
cinema when you attend."  Uh, I can't do that, for obvious reasons.  
I hadn't been aware that I'd be expected to do that, so I went back 
to the Terms and Conditions, and they didn't mention anything about 
having to bring the credit card with you.  And now I can't cancel my 
ticket because there's no link provided.  I've tried phoning, but no-
one answers at the office, and the only other number I've got is a 
particularly unhelpful premium rate line which keeps asking for my 
credit card details (ha!!).  There isn't even a "complaints" section 
at the website.

It's only a fiver, but it's more the principal of the thing that's 
frustrating me so much.  And heck, I really want to see the movie on 
the opening night.  I'm really worried here - can anyone suggest 
where to go from here?

Thanks for your time!

Hannah