My phone company apparently provides anonymous spamming service. New data protection rules forbid them to share your name and phone number, so they went ahead and created a service where marketers can call people without a phone number.

You want to reach females aged 30-35 in a city? Simply call or send an SMS from the API and you will be connected to a random one who matches your criteria.

At least, that's what my spammer told me when I insisted on telling me who gave them my phone number. Apparently, I gave the consent to be included in the pool at the time of purchasing some data package or something like that.