I engaged a plumber to light/fix a dodgy pilot light on my wall heater in a rental house I own. The call out fee was agreed upon. He called me when he was there to tell me he couldn't readily light it and that the heater wasn't up to building code, so it would be best to replace the unit. I asked him a few questions and he then threatened to report me to some agency about the wall heater. In short, I thanked him and we hung up. I then get an invoice from him above the previously agreed upon call out fee. He stated I had to pay it because he went into the roof space to have a look at the heater's venting setup. I told him I never asked him to do that, but essentially he held firm at the additional $50 charge. I paid it, but my question under Australian Consumer Law is "Is that legal?", meaning can he charge over the amount of an agreed upon call out fee 1.) without even ever having discussed it with me first and 2.) charge me extra to look at something I never asked him to look at? All I asked him to do was light/fix the pilot light, which he never did.