SHEIN Missing Refund, No Refund Given For Coat Returned

I am writing regarding an issue with my recent return to SHEIN. I returned several items together in one package and received a refund for all of them except one coat, even though it was in the same parcel. The coat cost £21.65 and was part of order number Gs019Q56B001XBL on my United Kingdom SHEIN account, charged in British pounds. SHEIN have stated that there is no receipt for this coat, which I find unacceptable because all items were packaged and returned together, and every other item from that same parcel has been refunded. If those items have been accepted and refunded, I do not understand how this single item can be treated as if it was not included. I have been a very loyal SHEIN customer for a long time and have never had any issues with returns in the past. This situation is very disappointing, especially as there is no clear customer service phone number or effective way to contact someone to resolve this. I kindly request that SHEIN investigate this return again and process the missing refund of £21.65 for the coat as soon as possible, or clearly explain why this item has been excluded despite being returned in the same package as the refunded items.