Very disappointed and dissatisfied with Toyota service and Customer Care

While I was on a country trip, My Toyota 2013 Rav's High Transmission Oil Temperature light came on. I drove the 90 km's back to JHB very slowly and booked the car in at McCarthy Toyota Woodmead the following day. They changed the Transmission fluid, but as I left the workshop the gears made a grinding noise. I took the car back immediately and Toyota McCarthy told me the gearbox needed to be opened for further inspection where they discovered the oil was black and burned and had damaged the gearbox and quoted R130 000 for a new gearbox. I felt this was unjust as I take my car for the recommended services. As a woman, reliability and safety is crucial. I asked whether the transmission oil had ever been changed in 188 000Km's and was told that according to Toyota SA it's not necessary. However, had the transmission oil been changed regularly this malfunction may not have occurred. The Service Manager recommended I escalate the matter to Toyota SA Head Office, I've escalated my concerns to Toyota SA and am being brushed off. Caxton Mabikwa simply forwarded my e-mail to Lungile Magazi. I need to follow up daily, when I mention my name and case number to the receptionist, I'm told they are in meetings, and my calls are not returned. The service Manager at McCarthy Woodmead has gone on 2 weeks leave and has left the 3rd party gearbox repair specialist to deal with me directly. Lungile explanation of the technical report is vastly different to what the gearbox specialist has stated. My frustration is that Toyota doesn't seem to care about their customers. It's almost 2 weeks that I have been without my car. Toyota Customer Care have not been in contact with the gear box specialist and have no interest in assisting me, saying I should deal with the third party gearbox specialist. If Toyota had maintained my vehicle properly, this malfunction may have been prevented. I am so disappointed with this brand. Buyer beware!!! Toyota SA Customer Care is shocking.