How do Global Shipping Program Returns work?

[pyrexparadise777]

Hello, about a month ago I sold a brand new and sealed Bachmann train set through Ebay's global shipping program. The buyer claims a controller burnt out on him and started smoking when he tried running it. He states he used a UK converter for the outlet. From what I read online he may have needed to use a transformer. Anyways whether he caused the damage or the unit was faulty, I'm afraid its gonna come down to a return. How does this work? Will I pay return shipping thru the program in the same way I shipped it? Or will I have to pay for direct shipping? Is Ebay gonna cover the buyer? This is a heavy and large item so I know it won't be cheap. Hope you guys can help. Thank you!