First go and break the head of that idiot! Then i think it is better not to ruin your car's transmission just for 1600 something bucks. Don't go to those TOYOTA idiots again. It'll not only save your labor charges but also you can get a very good gear oil in less money. Don't pay the mechanic more than 100 rs even if you have to pay. just go to some good oil change shop which has nearby a good mechanic and get your transmission oil changed. However, if you are going for OEM then it would definitely be costlier plus service charges. But if you go to the same Toyota dealer and complain them and get your oil changed from there again, it might also be lighter on your pocket. I don't know that the same oil can be drained cleanly and put into gearbox again or not..experts can better tell.
If you do it from Market, ZIC and GS gear oils are good choice. I have also changed my gear oil about a week ago from the market and feeling very light. 3 ltr of ZIC manual transmission oil cost me 480/ltr and no service charges.