I am not quite sure what your question is.
Not all sellers respond to messages - what are you trying to ask the seller?
Nobody here can contact the seller for you. The people who answer in the forum are other buyers and sellers like you. We don't know who the seller is.
You can't cancel and get a refund.
You can ask the seller to cancel but as they are not responding to your messages, that probably won't happen.
If you don't want the item you have bought, you may be able to send it back.
"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)