After 6 months there is no route for you to get your money back.
If it is a UK business seller, you could write to them or ring them but Ebay only has a 30 days returns policy.
"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)