On top of assuring everyone that it was an “isolated” incident, the company is working to pull all reviews compromised in such a manner. Whether or not that applies to the negative feedback those paid reviewers were expected to give to other, non-positive reviewers isn't mentioned, but you can imagine that it doesn't.
It's easy to criticize Belkin for the situation, and indeed a company soliciting reviews from people who haven't even used the product seems scandalous. Truly, though, it's not much different from what you see in mainstream advertising on a daily basis. In those contexts, however, most people are aware of the fact they are being sold something, whereas with user-generated reviews, people are often looking for honest feedback from a regular person like themselves who uses the product. At the very least, the company has apologized.