Search:

^ Get a call interceptor box, it only allows incoming from numbers you preset or suchlike.

Something like this -
...

The NHS is guilty - soon after registering at our GP noticed the wrong spelling of a name on NHS documents, this was quickly followed by quite a few unsolicited mailshots with the same error.

Same with the "no fault accident" phone calls - just a random try until they hit someone who has indeed had an event and falls for it.