I Wish To Complain Re A Membership Issue

I paid for costco membership on 7th January 2013 ( ref 98146148800) and was instructed to attend a costco store with an original copy of a current utility bill from the business address plus two pieces of busuness ID. Today (8th January 2013) I attended the store at Chingford, East London  at 1930 hours where I spoke to a surly woman called Jackie Francis. I produced to her a current gas bill with my business address on it, a bank paying in book with my company title and address on it, and a bank statement with my company name address on it. Mrs Francis told me this was not adequate as the bank statement was the same as a utility bill. I told her I disagreed and asked to speak to her manager. Her manager, Vince, then arrived and told me I needed to produce an invoice if I wanted membership. I told him that that was not what the email I had been sent stated. He then went away and consulted with another manager named Tommy who said that the two pieces of ID were not sufficient. I told him that I did not agree as I had complied totally with the email I had been sent and that I would make a complaint.