There are so many people that could have your number.

That one plumber you called that one time, who added your number to their phone could have added everyone in their contact list to WhatsApp.

Maybe you did a favour for someone and helped out their cousin and you gave the cousin your number and never talked to them again.

Maybe you had a friend you lost touch with and their number changed but they kept their address book.

You told absolutely everyone? Are you sure? Absolutely everyone and stressed to them how important this was to them?

Worse, are these replies which completely lack empathy. Such a lack of imagination as to how your number could leak. And a tone as if no one has anything else going on in their lives or more important things to do.

You do realize this is pure diffusion of responsibility? Something you can paraphrase as "It could have been anyone" is not an argument for this not to be wrong. I also believe the lack of empathy comment to be uncalled for. You not valuing your personal data doesnt give you the right to disregard mine. Especially with a friend, those dont profit off each other because of a personal disregard for the cost.

Its something worth considering, seeing as it has been two days and unsurprisingly nobody could come up with an actual justification for such behavior.