I'm in NL and had my wallet fall out of my pocket once at one of the bigger train stations. I realized within ~5 minutes, and basically as soon as I realized got a call from an anonymous number. It was the police, who had found my wallet with my ID in it and were calling me to inform me about it. Luckily I was still at the station and could just meet them and got my wallet back.

I couldn't help but feel extremely creeped out, and my girlfriend still to this day doesn't understand why I felt uneasy about it. "But you got your wallet back!", she says. "Of course the police know your number!". Having 0 privacy has been completely normalized, and I'm afraid we're far too late to do anything about it.

To be fair, your phone number has never been considered private information. You can open any phone book and find that info. They likely just looked up your name in the population register.