I was on the phone today with VZW Customer service with this issue today. They told me that you can go to vzwtext.com and set it up to block what ever number you want.
My issue is that I keep getting spam text sent from .com companies trying to "increase my size"... I would like to stop such emails for 2 reasons. #1, I don't want to get charged for these non verizon texts. #2, I have never had any complaints about what they are trying to sell...lol