You don't give much information - more detail would help other members to give you advice.
However, if you buy from a private seller and open a return case with a 'change of mind' reason (didn't fit, no longer want it etc.) then the seller can refuse the return and the case closes.
There is no need for the seller to correspond with the buyer.
"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)