Unfortunately, Textfree does not offer call blocking at this time. If someone is bothering you who is not a Textfree user, the best thing you can do is to create a new account. 

Textfree recycles old numbers from accounts that have expired. If you're receiving a lot of calls from people you don't know, they may just be looking for the previous Textfree user who had your number. Sometimes, all you have to do is answer and let them know that the person they are trying to reach no longer has ownership of your number.

If they are a telemarketer, ask them firmly to remove your number from their calling list.

If you're looking for how to block someone from texting you, go here: http://pinger.zendesk.com/entries/216452-how-do-you-block-someone-f...