Called them back and it was from Wells Fargo, they never leave a message and when yopu call back the first thing they want is your account number....no way

Recieved call, but didn't answer. Caller didn't leave message.
I'm getting lots of these type of calls.  How do I block them?

These guys have been calling for the last week, never respond or leave a message.

I have been getting theses calls for like a week 4-5 times a day.. How do you get them to stop..

I have had them calling from 8am to 8pm.  I have not been home, but I have seen that they call about every 30 minutes from my caller id.  It says Wells Fargo Home on the CID, but they never leave a message.  You would think if they were trying to get a hold of someone so urgently (it seems that way from the amount of calls)they would leave some sort of message saying what they want/need.
This morning I heard my phone ringing while I was feeding my kids breakfast, but before I could get to it to answer the voicemail picked up.  Of course they left no message, and I still don't know what they are calling about.  I have a checking account through Wells Fargo, but it is not overdrawn or anything, so I have no clue what they could be calling about.  It is getting frustrating though.