Uber — uber has cheated as their driver collected double amount

Address:

Ernakulam, Kerala

Please ask your in support staff to reply only on this points which I furnish below.
I would like to share a bitter experience I had with Uber, it happened almost before a month but the customer service could not solve the problem all they know is to send irrelevant messages.
On 24 may I booked cab through Uber from my mobile, the cab reached on time and I boarded it but on the middle of my trip I noticed that particular trip is canceled and to my shock the driver asked me to pay double the amount which was quoted to me during booking. When argued the driver showed me the higher amount which was displayed in the Uber device and asked me to take up the matter with customer care. I immediately contacted them to refund me the difference in amount but repeatedly I got a reply that my cancelation fee is waived which is ridiculous.
The following points are my concern and please investigate and I expect a positive reply.
1. Who has canceled my trip?
2. If the trip is canceled why did the cab arrive at my pick up point?
3. How did the driver get a different amount in his Uber device, which was more than double of the fare quoted at time of booking
4. Did Uber investigate this issue with driver on the very first day as I have made complaint immediately?
5. What was the outcome of investigation and Uber try to retrieve my extra amount from the driver?
Kindly reply to all of my queries as it is genuine grievance of a mishandled customer