Oh dear, you have a lot to learn about acceptable behaviour on ebay.

It is one thing to ask a seller what a Private Listing is all about but telling them that you have been advised that they are participating in shill bidding is really not on.....and more so when it has not been proved that they are doing this

I suspect that the seller has now banned you from bidding on any of their listings.   And I suspect you have also been placed on the Blocked Bidders List of many other sellers who read these boards.

You just cannot go around accusing sellers of wrongdoing without a lot more proof than the fact that they have Private Listings.