Bro, I must say I have suffered same fate using the POD model. I also sell wrist watches across the Konga, Jumia and Kaymu. The returns on Konga lately have been very annoying. Some customers place an order for an item, you confirm their interest and they still fail to receive it when it is delivered to them. Some do not even pick their calls when the delivery men try to reach them. The returns are not as a result of quality issue but due t the inability of the customers to receive what the ordered for.
The worst thing that POD has enabled them do is that, customers now order the same item from 2 or more stores and pay/receive the one that is delivered first. The other sellers that shipped to them will have their items returned.
The fact remains that POD is not a good business model. If you want to enforce customer confidence/trust, run a trusted ESCROW service. Customers pay ahead and when they have issues with the quality of the item they ordered for, they return it and get a refund within the stipulated time frame covered by the return policy. That is the way to go.