What did you believe the phone call was about?
I would assume that they took your bank details as they have taken the money which would be persuasive that you agreed to purchase something and gave your bank details to pay for it accordingly.
Can you get a copy of their terms and conditions to check out any return or cancellation policy.
Have they sent anything out to you? Given the nature of the pack, I'd either not want to have delivery or at least don't open anything, in case they are difficult by making out you could have copied the docs and tried to get your money back etc...