Over charged first trip taxify

I used taxify for the first time on the weekend, I app**** my promo code of R150 and my estimate to pay to my destination was R30. I used my debit card for the transaction. A few minutes after my ride I received a bank notification that R200 was debited. That is more that the estimated price without the promo code. Code was used and I was still billed for the full first trip. No response from emails or support team of taxify and phone numbers just ring no answer. Terrible service. Uber much better and trustworthy.