Just contact them and ask what’s happened.
Call the customer service. It happened to me, they only refunded 2 items instead of 4 when I contacted customer service they said their workers said they only received two items and I said that wasn’t true because all 4 items were in the same bag . They then said they will investigate by looking on the CCTV. 3 days later they refunded the other 2 .
Thanks everyone, I’ve emailed them
Update: i just received a response claiming they have checked CCTV and there was only 2 items and not the other 2 so they wont give me a refund. Lost as to what to do. I definitely returned them all in the same parcel.
Yes somtimes this can happen. But calk them anyway just to be sure