Wish complaint: return and refund

For over a week I have asked wish for a refund on an item I returned. Wish have had the returned item, item number and reason for the return. They have also had the tracking number of the returned item which shows they they received my returned item on 23rd feb and a signature was obtained as I returned it as a recorded delivery. They received the returned item a month ago but I still have not had my £18 refund. Wish keep delaying things by asking for the same information about the return etc over and over again and just sending me automatically generated messages again asking for the same information and they have also refused to open up an official complaint. Wish have had photos and item numbers and a description of the returned item and they have had my tracking number and a signature upon my item’s return so there is no reason as to why I have not had my full refund