Several factors can account for why an iPhone’s battery simply refuses to charge. By that time, you typically have no choice but to bring it to someone who is trained in iPhone repairs, in Melbourne or elsewhere, as well as battery replacement (since an iPhone’s battery can’t be replaced by an average user). Before your battery gets replaced, here are some steps that can be taken to try and sort the problem out.
First, you may be dealing with a relatively simple (though easily overlooked) problem: a dirty Lightning Port. A good amount of dirt, lint, and other debris can accumulate inside the port and prevent the contacts from connecting perfectly. Any small tool, e.g. a toothpick or the sim card remover which came with your phone, may serve as a makeshift lint remover.