Charge for incorrect ride and now a mysterious invoice

A simple comfort ride from OR Tambo has caused me hours of wasted time. I was charged correctly. Then the charge was reversed and I was incorrectly charged R546.79. After an awful lot of to-ing and fro-ing, the amount overcharged was credited to me the following day. Now I see I have an invoice for R705.00 For what I do not know. I cannot get an answer from Uber