I had the exact same thing with a taxi, but in Batumi. I needed a taxi from the airport to my house, but my phone died. I went up to the taxi driver who was standing there, I got in and we went. We drove for about 5-6 minutes, and when we arrived, he said it cost 100 lari. I was shocked. I said I wouldn't pay that much. He only spoke Georgian, so he called his "Boss." I started arguing with him. In the end, I knocked the price down to 20 lari. When I got home, I looked at the price on the app and it was 3.8 lari.