Cricket doesn't have the ability to block numbers! WTF?!
A person I know thought it'd be hilarious to flood me with text messages. So I got sick of it. I called Cricket and was told that Cricket does not have the ability to block phone numbers. What? What's stopping them? Also, is the rapid receiving of text messages bad for my phone? (Samsung Messager II)
So here's a comparison: If you want AT&T to block phone numbers for you, you have to pay them 4.99 a month. I don't know about the other major carriers, but it wouldn't shock me if they charged for this service too.
Here's what you can do: Add the number to your contacts, and set the ringtone as silent. Sure, it doesn't block the calls, but then your phone will not ring when they call or text.
The only thing that can be bad for the rapid receiving of text messages is the battery.