@jeop10 - The whatsapp "leak" looks to be the result of a scrape.
So someone tried (for example) 00 000- 000-0000 through 99 999-999-9999, confirmed the ones that used whatsapp, pulled the names down, and collated the data. (Obviously they could be more targeted and quicker than that as not all numbers are used, etc).
Essentially they're selling a phone book of names and numbers.
Damage Control: Don't accept messages from people outside of your known contact list. Don't respond to cold calls.