Blocking numbers?

So, recently my cel phone number found it's way into the hands of someone I didn't want it to. I want to know if there is any way to block this number from calling and texting me. I know there is an app that can do this for jailbroken phones, but mine isn't. If this can't be done through my phone, can it be done through my service provider (I'm with Rogers)? Any help at all would be greatly appreciated.