Twitter is changing their timeline to be algorithmic instead of chronological, rather like Facebook did some time ago.  Matthew Lynley reporting for TechCrunch:

Twitter today is unveiling a new Twitter timeline that shows tweets at the top that the service recommends, instead of the most recent tweets. They’re designed to be the best tweets that users may have missed based on what Twitter thinks you care about. […]

All this comes on the heels of a massive backlash against the move, which was first reported by BuzzFeed, in the trending topic aptly named #RIPTwitter.

If you don’t like changes a service you do not pay for makes, you don’t have any recourse other than leaving. I encourage you to do so.