Yes- but BACKUP YOUR SITE FIRST.
Are you still in development? Or is this a live site with live vendors and orders happening?
If you are not too far along in development, you can also completely reset. I know this would involve having to restart with everything , though, so not the ideal solution.
there are still some clingons form that development he did, and/or WooCommerce product Vendors, and it is interfering with your dashboard pages. Your dashboard pages do look different… our standard pages with Storefront theme you can see here on our dev site: dev.wcvendors.com and you can see that your pages look different.
If you know the specific alterations the dev mad,e then you can go through and remove them. However, I do not know why it is interfering with WC Vendors Pro dashboard pages… they must be using the same classes or something.
Or- look through your database and drop any old WooCommerce Product Vendors tables that may be lingering.