Safari Redirects All My Web Tabs To Spam Or Popups

Got an iPhone 5S, iOS 9.3.1. Ever since yesterday when I was casually browsing Facebook Safari started to redirect 50% of my web browser requests to some ad site called oneclick.com, which then directly redirects me to various annoying popus stating that "OMG YOU WON THE LOTTERY CLICK HERE TO CLAIM YOUR 100 MILLION PRIZE" or some other scamp > : (

I have tried:

- updating to latest iOS

- tried turning phone on and off

- updated all apps on the phone to latest versions

- made sure all popup-blockers in Safaris app settings are turned on,

But nothing 😟

My phone is becoming useless by now. Only thing that's helping a little bit is using the AdBlocker app, which at least only makes the site completely blank when I'm forcefully redirected to a scam site.

What can I do?