sign in at My Verizon> My Services at top of page > Spam Control.
There's 2 tabs:
- Call & Messaging Blocking
- Internet Spam Blocking for emails
You can only block up to five phone numbers at one time. Also, blocks will expire 90 days from the date you set your first blocked number. You can reestablish Call & Message Blocking, by visiting My Verizon after the previous blocks expire.