refund, upfront cost

My original upgrade order was cancelled as they couldn't fulfill it for at least 6 weeks. (It took me 5 different live chat conversations and 2 phone calls to gain clarity about the order in the first place). I agreed to cancel and was told I'd get a refund for my upfront cost of £19 within 5 days and I went ahead a re ordered a different offer with no upfront cost. I successfully received this order. However still no refund although I have verbal and written confirmation I'm owed not to mention the PROCESSED payment of £19 showing as carphone warehouse on my bank statement. Now different ID representatives are saying different things most recently that it doesn't exist. I need help urgently?