Mobisy's Spam Manager promises that once downloaded you won't get a single nuisance call or text message ever again, or at least not a spam one anyway.
The program is able to intercept all calls and messages it views as spam and block them without you knowing. It does this by secretly and cleverly telling the phone if the number matches one that is listed as spam.
It then either blocks the call or directs the message into a separate folder that you don't need to worry about.
The one word of warning with Mobisy's Spam Manager is it does require you to do a lot of the work yourself.
When you first use it you can open a folder to see the numbers that the software is blocking and similarly with text messages. But the cover is a bit basic.
What it really wants you to do is add numbers to the blocking list, eg those people or companies who keep bothering you. Transfer these numbers to the folder and Mobisy's Spam Manger will reject all their calls.