Double debited for Ticketmaster transaction

On 30 November 2022, I purchased tickets to an upcoming show. The ticket sales were opened early exclusively for Discovery clients. I made my purchase successfully. However, after checking my bank statement a few days later, I see that I have been double-debited, ie. Charged twice for the single transaction. I sent a query to Ticketmaster for a refund to me, however they have mentioned that they had only received one amount, ie the single payment for the single transaction. I then reached out to Discovery Bank telephonically. I was advised that two exact transactions were processed at the same time, and they will process a refund request for one of the transactions. It has been more than 2 and a half months since the transaction and two months since I tried to get help from Discovery. I called again in Jan 2023, no help or update. I'd like to find out how to receive a refund, and who will be liable for the interest charges on that transaction for the last 2.5 months?