Uber Driver ********* + Theft

I took an uber for a small trip (R20) and told the driver that I would be making a second trip in 15 min. He advised that I don't need to use the app as he would take me. He charged me R58 and I agreed. After we discovered the address I had initially entered was incorrect and was an additional 3km, he told me that he would charge R100. I told him I didn't have the additional cash and that I would have to ask at home for more money. he told me he would charge R170. I had to get back home and get my wallet in order to get to an ATM. Now my charge was R200. I only had R100 available and he took my phone from the charger and said he would return it once I had the cash and told me to write his number on a piece of paper. He was intimidating. I had no choice. Once I got the full amount, I called him, he said he was already in Soweto, I should call the next day. after a few attempts of no responses he turned off his own cell as well as mine. I have not been able to get hold of him since. All my personal information is on that phone and I am out of touch. I only know the drivers name, car model and make. I am losing out on so much without my phone and feel this is ********. How can I get assistance without having to go the cops? This has been a terrible experience for me. I want my phone back!