Vendor 1 has Product 1. Customers never hear from Vendor 1 and the vendor falls off the face of the earth yet still has customer money. Heck, they might even be "out of business."
...is there a product offered at all if customers have huge problems buying the product? They might as well be out of business. So why can't Vendor 2 offer a product similar to Product 1, which couldn't be provided by Vendor A?