I do not make my items but I give full descriptions of them and I do not take returns, normally. There are always exceptions but I don't advertise them and I listen to the buyer and go from there.
When a buyer says they didn't receive the item, send another - I say hold up there lets track that package. If the carrier has failed to enter the package in the system with my delivery comformation - I put a trace on it anyway. At this point it is the post office's responsibility because they failed to do what I paid them to do and they are happy to try and trace the package.
I write this to my buyer. If the post office can't find it - we persume it is lost in the mail. The post office then requires the buyer to register a lost package with the post office online services and to report it to their local police department.
I hae been amazed at the lak of enthusian on the buyers part when I tell them what needs to be done before we can move forward. Often, I never hear another word about the "missing" package. I have had 3 buyer complaints and all 3 did not move forward in the refunding of a lost package process.