I installed Whatsapp messenger on my tablet as my wife likes to use it to share things. I try and avoid it and Facebook and it's annoying messenger. So when a 'messenger' alert popped up on my 'phone from someone I knew, I assumed it was legit. It wasn't. I only clicked once on the Android Facebook banner and did not click anything else and it has made a proper mess of my Wileyfox phone.
Hitting the power button as soon as I saw something unusual preserved Google and other online things from damage, but the phone.......

So a factory reset did not get rid as it still tried to encrypt everything (even though I'd deleted it) and required not only a complete Android image, but repartitioning the Linux based flash memory. ADB, the Android standard tool could not fix it, so I've rooted it, installed TWRP and have almost got a working OS. Almost.
Very nasty and unrecoverable for most - I have not succeeded yet and have some history with reflashing various phones over 10 years on and off. I was running Android 8 (quite old) and am fairly sure I had AVG in the background and of course daily Google security updates.
It's probably time for a new one, but I hate scrapping working hardware that is doing a job
