Delete all positions of the supplier with which we no longer work

Hello, if you have the supplier "Acoustics (API)" displayed in your products, then this is most likely due to the fact that you specified this supplier in the automatic action of importing products as a constant http://joxi.ru/l2ZXoVauzX9L5r
Change this setting to the code of an existing supplier and the products will be loaded by the required non-remote supplier
By default, vendor products are removed when a vendor is uninstalled. In your case, it happened, cleared, but loading by settings loaded exactly according to the specified provider
After changing the supplier, write here - I will delete the records of this supplier from the supplier's products.

Hello Maria. We are talking about the South of the stock, the supplier was filled in manually without api.

This provider is not remote on your system

And how to remove it then correctly?