Have you paid?
If you have paid, then you will have to wait until one day after the latest estimated delivery date and then open a case saying you have not received your item.
The seller would have to log into their account to add that messaage to their profile.
"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)