It depends on what you bought, if it was a private or business seller, if it was new and whether it came with any warranty.
Legally, for an item less than 6 months old. irrespective of how many times you have used it, the seller should offer a repair or replacement, not necessarily a refund though. Do some googling to check your rights and contact the seller.
Ebay give you 30 days to return a faulty item, so you can't open any sort of a case through Ebay.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)
