Seller Calling to switch attorney or deal cancel

[Zulu Black]

I recently put down an offer on a property and it was accepted. As I was doing my due diligence, I got a called from a seller (also a RE agent) and told me she does not want to work with my attorney because of a known rep of him slowing things down and somehow jacking up the seller side legal fee. She even threaten to cancel the deal even after the contract has been signed if my attorney starts his usual "habits". I am honestly quite shocked about this. 

What should I do in this situation? Should I consider switching attorney to make things smoothly? I've never worked with my attorney before and I haven't signed a retainer agreement with my attorney yet. Found him online with good decent review.