Wish complaint: Refund wanted

Wish are stating I’ve received an item I’ve not and refusing to refund me. I’ve tried 10,20,30 times to talk to the customer support but its like hitting your head up a brick wall. The original hoodie was not available so I was given the option to change it for something else. That’s fine but this item hasn’t arrived. I’ve done as they asked and contacted my post office and neighbours but they don’t have it. I’m getting really angry and frustrated now. I just want my money back. If they are adamant I’ve received it any are they asking me to check round people. This has been going in for a few months and I’m fed up to the back teeth. It says it’s been delivered. The only issue is a huge bag arrived with lots of bags inside so as happens when things come from China there are times a parcel is missing. This is 1 of them. So now I’m paying for an item I’ve not received.