I had mine blocked too
I got one bit of spam, and then the next day I had a wrong number picture message from some girl trying to send it to her boyfriend. She was pretty explicit about stuff I didn't need to know. I deleted it instantly, and then got a call from her while she was trying to see if her boyfriend got the picture. I told her he hadn't, but I did and asked her to please check her phone numbers more closely. She was pretty embarrased. Later that day I had text and picture service turned off and the carrier didn't charge me for those transactions.