Billing charges

hello there

I recently had a bad experience using the uber service. i had attended an event with a group of friends of mine and we thought it would be best to return home using a uber. i decided to request the ride using my own phone. once the ride had been confirmed,uber deducted R599 from my account upfront. Unusual because they always deduct after the trip. upon arrival at our destination,they further tried to deduct an amount of R810. fortunately or unfortunately..the amount wasnt deducted due to insufficient funds but, you can still see the charge when i open the app. im unable to see my receipt of the trip as well! my fear is that they will deduct the R810 as soon as there is funds in the account or when/if i decide to request another ride!!