There may not be any tracking.
You say the seller sent the item untracked so presumably there won't be a tracking number.
Is your item late?
Check the email you got when you paid for the latest estimated delivery date and, if the item doesn't arrive by then, start an item not received claim.
"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)