Level of competency of Toyota Mechanics in question

In the past I believed that there is no better car to drive than a Toyota....until last year (2018). I had taken my RAV in as I thought there might be a slight problem with the gearbox. Only to discover that what I heard initially is actually normal for an automatic car. Nevertheless they told me at Barlow World Menlyn I needed to replace the gearbox mountings. Unfortunately I am a woman with not a lot of knowledge about cars. So had them replace my gearbox mountings. When I showed the gearbox mountings they replaced to a mechanic he said that there was absolutely nothing wrong with the mountings. I discussed this with the manager who agreed and gave me a refund. That was the better part of the service. After I got back my RAV I noticed that there was a noise that was not there before. I took the car back and now they said it is my car that is old and a coincidence that this noise started when I got my car back from them . Note that this noise was not there before I took it in the first time. The bad experience I had with this branch lead met to take it to McCarthy Toyota Lynnwood. They "noticed"a few thing that were wrong. I paid just to get my car back with exactly the same noise. I tried 'n third Toyota workshop. I was told that I needed to replace the gearbox which I did. After spending another R45,000 the problem (noise) was still there. They then discovered that the gearbox mountings was put in incorrectly( by Barlow World Toyota Menlyn. I was so annoyed and fed up with the situation I decided to buy a new RAV. After a few months I needed to refill the oil and phoned to enquire if this is normal for a brand new car to use this much oil. They informed me that there was a recall on the engines of this model. They then measure the oil usage in the middle of 2019 ( the car was 7 months old) and told me that there is definitely an issue that the car use to much oil and they needed to replace the engine. By now I did not have a lot of trust in Toyota mechanics because of past experiences and I decided to wait until I get a second opinion. 6 Months down the line the oil level was still full. So my question is I never topped up the oil since they informed me that the the car uses too much oil, why was I told that the car use too much oil by measuring it every 500km (by the mechanic himself? I have lost all trust in Toyota. If it was not for the mess up that happened at Barlow World Toyota in the first place it would not have been necessary for me to buy a new car.