My factory is selling my custom product to other buyers

I have a custom/PL product that is produced by a factory in China. I’ve recently noticed the product being sold at Kroger’s and Kohl’s (not me) for almost half the price that I sell it for on Amazon. Presumably, my factory is selling my product verbatim to another buyer.

What can I do to stop this?

I’ll have my attorney file cease and desists to the infringing brand owners on both platforms for trademark and copyright infringements, but, I don’t want my factory selling my product to others.

Do Chinese factories typically respect your requests not to sell to others? Is it worth a flight to the factory to talk in person, or is it customary to just sell to the highest bidder?