Export of Cars

As per Recent FTA guideline, Export of Cars of multiple sales of cars resulting in single export, only the final supply can be 0%.

Practically, resident of uae purchase cars and export to their overseas customers and revert to the dealers with export papers that cars exit hence refund the vat and make supplies as 0% becuase cars have been exported by them. 

In this case, what dealer should do becuase he sold to them locally & risk and reward transferred and what customer should for refund either contact to FTA eventhough he is un registered?