Yep, you can add the number to your Contacts/People, then press Menu > All calls to voicemail, and as it says, all calls will go straight to voice mail.
Another option is to log into your on-line MyVerizon account and look under Plan, then click on Block Calls and Messages. Add the number in the appropriate space and click Submit. The block will remain in place for 90 days, but you can re-block it after 90 days if you need to.
If you use the call block on your MyVerizon account, they won't be able to text you as well. They will get a message that the call can't be completed or something similar when they call you. Not sure about the text messages though.
I believe a Verizon Wireless employee gave a more detailed answer in an older discussion in the community if you want to search for it. Which might have been a good idea to have tried before starting a new discussion.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
Great question davet101! I have an answer for you! You can block up to five numbers from calling and messaging you for FREE! You can go to vzw.com/safeguards or login to vzw.com/myverizon and click "Block calls & messages" to add the block. We're here if you have further questions!
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