Barracuda Networks is at it again: Any Suggestions as to an Alternative?

["John Palmer \(NANOG Acct\)" <nanog2 () adns net>]

OK, its been a year since my Barracuda subscription expired. The unit still stops some spam. I figured that I would go and see what 
they would do if I tried to renew my subscription EXACTLY one year after it expired. Would their renewal website say "Oh, you are at 
your anniversary date", and renew me for a year?

No such luck: They want me to PAY FOR AN ENTIRE YEAR for which I did NOT receive service and then for the current (upcoming year). 
Sorry - I don't allow myself to be ripped off like that. Sorry Barracuda - you get no money from me and I'll tell everyone I know 
about this policy of yours.

I posted an article about this unscrupulous practice on my blog last year at http://www.john-palmer.net/wordpress/?p=46

My question is - does anyone have any suggestions for another e-mail appliance like the Barracuda Spam Firewall that doesn't try to 
charge their customers for time not used. I should be able to shut off the unit for a year or whatever and simply renew from the 
point that I re-activate the unit instead of having to pay for back-years that I didn't use.

Thanks