I Keep Getting Calls from Unkown Numbers from WhatsApp Users

I'm constantly getting a call on WhatsApp or a message saying hello. When I look at the number, I see that the country is Nigeria. What about end-to-end encryption? How do I call or message me? "Privacy and security is part of our DNA. That's why end-to-end encryption is built into our app. When end-to-end encrypted, your messages, photos, videos, voicemails, documents, status updates and calls are prevented from falling into the wrong hands. It is possible." You know how to write. I do not accept any responsibility of my own that may be connected with this search!