Declined Apple Pay transaction still posted

I tired to make a purchase over the summer with Apple Pay and the POS system declined it. I used my debit card instead and it went through fine. Both transactions showed up as Pending and then eventually Processed within my Bank Statement, even though only one purchase ended up actually taking place. The recent transactions on my Wallet/Card summary on Apple Pay showed it as Declined. My bank statement even shows a difference between the two transactions, one being a "Mobile" purchase and the other being from my debit card. I've been fighting with my bank for three months to get this sorted and get my refund, but they refuse due to "no issue" having taken place. Has this happened to anyone else?