There is an application in cydia called 360MobileSafe. It will block anything you want to block. Calls & texts is a speciality. It's just on the market. Real good application. The translation isn't great, spelling mistakes but if you can live with that then try it. You'll like it. It's also FREE here are a couple of screenshots for your convenience.
I might try this new app. I currently use iBlacklist. I like it because you can still access the texts and see what they say. iBlacklist does cost money, but its worth it imo.