I didn't recognise the caller number, so assuming it was a telemarketer I answered the phone with "hello, may I ask you help you" (hoping they might they'd dialed a business rather than a private number. This almost always works & it did - they hung up in my ear.
I tried ringing them back, to return the favour & harass them, but went straight to their phone message service "this umber has incoming call restrictions".
So they can call you, but you can't call them - Arsehole!