Where is option to list an item at a fixed price WITHOUT accepting best offers?

[blfsoftwaresales]

I have seen other posts say to click "advanced options" on the "revise your listing" screen and it will alow you to uncheck a box that says "accept best offers," but this is not showing up on my listings. I cannot find any option to remove this and I keep having people send me lowball offers when I only want to accept a fixed price. Thanks. 

[partial*eclipse]

You might be able to do it through the bulk editor. Otherwise, the only way to avoid it is to use the Advanced version when you set up the listing.