I am hoping/assuming that you returned it through an Ebay case.
You need to go back to the case and ask Ebay to step in.
As long as tracking shows the item has been returned to the seller, they will refund you from the seller's linked bank account.
"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)