Help!

Description

Hello not sure where to start with this but basically, on April 3rd I placed an order for car parts with a seller. Cancelled it the next morning as realised it wouldn’t fit. Seller agreed to cancel and did so on the 4th of April. However no refund was ever issued. 3 weeks later one day before deadline on my refund seller sends out a parcel to a random address. Now eBay has suspended me as I sold a few items but stated before listing them that I wouldn’t dispatch till my issue was resolved. They agreed. Now I have sent them proof from Royal Mail stating delivery never came but they have refused my appeal and now I’m suspended for not sending out the items. What do I do from here?