In Germany it's a department of https://en.wikipedia.org/wiki/Federal_Network_Agency who deal with complaints. They can switch off a phone number and give 300.000 Euro fines against companies.

Year 2020: 40k complaints about 18k phone numbers (12% from outside Germany) for predictive dialing. 155k complaints about phone spam (company trying to sell you something). 1.3 million Euros in fines. https://www.bundesnetzagentur.de/DE/Vportal/AnfragenBeschwer...

I received one spam call in 2020.