Who to contact about Turkish Airlines refund?

I booked a flight departing from Dublin from Turkish Airlines in January but the flight was cancelled because of weather. I requested a refund which was processed on February 18, 2023. However, the refund was made to an Ulster bank account that was in the process of being closed at the time of the refund. Ulster Bank automatically initiated a chargeback on February 21, 2023, returning the funds to Turkish Airlines' bank account.

I contacted Turkish Airlines multiple times, explaining the situation and asking for a refund through an alternative method, their responses have simply been to state that the refund was successfully processed from their end. Ulster Bank has assured me, however, that the refunded amount is with Turkish Airlines' receiving bank.

I tried contacting AviationADR but after over two months of no reply, they eventually replied and said that they can't look at the case because "Turkish Airlines are a non-EU carrier and the flight didn't depart from a UK airport".

Where do I go from here? I have wasted a lot of time on this so far and I am getting nowhere.