Most prisoners in the U.S. are allowed to use a cell phone any many find it a good way to pass the time and have developed scams. I have been getting a number of calls and have had to install a blocker. There is a company called SECURTEL that prisoners can use to do their hijinks.
Your iPhone has a blocker for unwanted calls, @Lon Tanner . What it does, is send any unknown calls straight to voicemail, and if it is an important caller, they will usually leave a voicemail. This has worked really well for me, and I no longer get those silly calls about my car windshield, or lack of Medicare insurance that we all get so tired of. I did have to put any number that I thought might be calling me that I didn’t want to miss, into my contacts, and I add as there is someone new that needs to go in the contact list; but it is well worth the effort. We have T-Mobile, because it has a discount and special benefits for veterans (my daughter is retired military), and T-Mobile also had a blocker, so we have both turned on.
I never pick up. I let my answering machine pick up after two rings. I get few calls anymore. They figured I must be dead.