When WhatsApp first shown (not owned by Facebook yet), some cellphone companies literally sued them (and lost), claiming all sorts of random bullshit.
Now everyone here uses WhatsApp, some services are WhatsApp only, as in... the service is basically a bot on WhatsApp and you send commands to that bot using WhatsApp.
I tried to not use WhatsApp, but when I saw the SMS fees... well, WhatsApp did forced them to bring fees down, but not by much.
I also tried to convince people to use other software, it worked partially...
1. Telegram, people here use this whenever WhatsApp is down, then they delete it again.
2. Kik, I was using it to talk to some poeple in other countries, for various reasons slowly this failed, the most bizarre one was a friend that lived in Alabama in US, seemly her phone company (AT&T I think?) detected her Kik usage and charged every single video chat we had as if it was an international phone call... as you can imagine this killed our Kik usage quite fast, we now use only Discord and e-mail.
3. Discord, only young people use that.
4. Slack, only works for work.
5. Matrix, Irc, etc... nobody I know in person uses it, people just refuse to use "techie" stuff.
6. ICQ, MSN, AIM, etc...: these were wildly popular here, ICQ was kinda killed by MSN, that then was killed by MS themselves for some reason. Nothing replaced MSN here.