Is it possible to check the base of mobile numbers for accounts in Viber, WhatsApp, VK, FB?

Question

Facebook

Can you even suggest a ready service?
This is a standard task for modern business. It's strange that nothing is being looked for right away.
Once this issue is solved by handles, then, in theory, automation is also possible.
Thank you very much in advance for your attention.

Answer 1

Handles decide ... There are restrictions, if the user has restricted access to personal data, then you will not receive this data. You will not argue that you can get the phone number of any network user with pens!