Amazon Buy Shipping Seller Protection

I always buy my shipping from Amazon,I sell 1 product average price is $205. Lately I have had a rash buyers not getting their shipment or it’s late they want a refund. I believe the procedure is I wait for Amazon to refund the buyer then I can file a claim if AMZ chooses to stiff me . I ALWAYS ship on time . How and when do I know if AMZ is going to cover the cost. ? Where do I find documentation of the transaction. T