2013 Ford Ranger 2.2 Chassis Rust & Tracking Issue

I have a ford ranger purchased exactly a year ago from a dealer some distance from me. I've just got it back from its first service and my local garage have told me that there are numerous signs of rust across the entire length of the chassis. They also say that the tracking is out and has worn down the inside tread of one wheel.

I thought all chassis these days went through a process of zinc plating. Should this all be fixed under warranty and where would I stand on the worn tyre issue as Ive only ever used the vehicle on tarmac roads. Thanks for your help.