Make sure that you also put the blade back in correctly and if it is an Olfa that the ring and screw on piece are on correctly. I can never remember which is the correct way but you can check it out on their website.
I too bought this thinking it would be great. While I didn't think it really sharpened my blades enough, it didn't make them so they wouldn't cut.
I know these aren't cheap and it is an expensive lesson. I don't still have mine but if I did think I would at least send an email to the company.