Refurbs are usually only supported by the seller, not the original manufacturer. See what Tyler says, then decide about return, bite the bullet for a new blade, or live with what you have.

Jake here has recommended a refurb dealer called Big Sky Tools, that has been great. I've bought a few things from them and been very happy. They grade their refurbs, A B C, so you know what to expect. I got a few refurb 4.5" grinders that would totally pass for new.