I recently joined a local table tennis team and they manage 
  the entire team via WhatsApp, so I had to start using 
  WhatsApp again if I wanted to be involved.

I can't think of an organization I would join if they respected me so little as to insist I use a Mark Zuckerberg product. I don't know about elsewhere, but in my country, people who haven't yet quit Facebook tend still to be aware that they should.