Hoover Windtunnel 2 Extra reach?

The hepa filter clogs continually and stops turning. We have had this cleaner back for warranty service three times untill the warranty ran out. It would work a couple of times when we got it back then stop turning. If I were to take the hepa filter out of the cleaner do you think that it would still work?? We have written Hoover they admit that it is of poor design but refuse to replace or refund. Can you help??