Bolt (Taxify) App overcharged R300

I am absolutely appalled and furious that my money has been ******. a trip from Lanseria to o r tambo was quoted on the bolt app from R400-R500. UBER WAS R550. I tried to use bolt for a change. I chose bolt because it was cheaper. When I got to the airport I got a bill of R673. Please refund by COB today.