You need to think of the system like a game. Imagine if you are playing a game with a cheat. Unless someone says something, your account won't be flagged or investigated. It's the same theory. No one is going to hire 20x staff just to sit there and monitor your behaviour. You are one of ten thousand drivers going online at the same time.

There must be a trend that you have repeatedly offended. That's why you are flagged, so you are filtered to monitor. After a few weeks they will deflag you then you can do whatever you want until the next complaint comes.

I normally get rated down or complaint when I hold the order too long. Meaning when I make them wait for 10 minutes or more then I cancel (because I am on a trip). Normally, even for the airport, I will cancel immediately giving them a chance to find another.

I would assume you are unlucky. Prior to you, there must be a lot of people cancelling until the rider got super pissed. So they must have taken LRT back and while on the line he wrote the complaint of their experience. You may have just been collateral damage from other drivers fault.

Normally I will strike first, making default templates to type to the CS explaining such and such. Copy paste then send. That's the first impression you want to give the CS to invalidate the intention of the rider. Remember, they must read thousands of the same complaints daily so in their mind they already drew a conclusion before they read the second line.

One of the most powerful lines I use is "if the answer is not satisfactory, I will write an official complaint to relevant departments that regulates....." - I tend to get my way when I use that lol.