Charged over than expected, reckless behavior, drinking and driving

I had a very bad experience with taxify, I requested a taxify from citylife Smith Street in Durban to Unisa main campus, the ride was supposed to be R19 because I had a promo.. I use taxify regularly, but this is the first bad experience ever... This guy Mahle, number plate ND728212, this guy's was drunk and didn't know the directions, the music was loud so he hardly heard us when we directed him even thou we complained about music because he was unable to hear us. He took a long roote to Berea where taxify updated the ride price, and that was fine (R31), when we reached school my app told me I'll pay R31 and he said to me his app says R52 but refused to show us and he talked about his app not wanting to work and staff but he charged us R85.. We refused to give him because he didn't make sense, he then drove off from where he was supposed to drop us and threatened us because his doors were closed.. It was me and a friend who is a female, we were scared because he wanted to drive us where we don't even notice the direction.. I'm so disappointed and angry... Bear in mind this person was drunk, so our lives were in danger because we only noticed when we got in to a car that he is drunk, but we were rushing to school because we were already late... I'll make sure I follow every step you take because if he can do it to me, what's gonna start him from doing it to another person... Taxify, discipline your drivers because they will bring your name down...i need feedback and I won't stop till I get feedback.. Thank you!