Deducting double payments for food

On the 24th of October I ordered food through Maar Delivery and I paid with my credit card. The money was deducted from my account and then on the 26th of October they deducted the same amount again from my account. I’ve been in contact with my bank and they confirmed the money was a duplicate payment to them, but Mr Delivery can’t find the payment and says it’s declined. I haven’t received that money back this whole time. Every time someone actually decides to email me back I have to attach a new bank statement. My banking costs are getting ridiculously high with all of the statements I need to get from the bank. It’s been weeks and still they don’t refund me or anything. They just want new statements.