If you blocked the number via the device, it sends the call straight to voicemail.
If you blocked the number via the block option in your My Verizon account, then according to that page:
Customers who call your number will hear: Welcome to Verizon Wireless. We're sorry the number you have dialed has calling restrictions that have prevented the completion of your call.
Customers who text your number will receive the reply: Message Failed.