No refund received on out-of-stock items

Ordered some items on the 21 April 2024. On the 27 April I received an email that some items are out of stock, and I must advise them if I would like to get a refund which I opted for. 30th of April they requested my banking details which I sent the same day. 2 May 2024 I received the acknowledgement of the banking details and that the turnaround time for refund is 7 to 10 working days. Till this day I have not get my refund from them.