Uber India — cancellation charged unfairly

On 23rd july, i availed 4 times uber and in two of the incidence driver decided not to take the once but i was charged for cancellation.
When i posted the grievances, there was no response from uber. After three days, till now its unresolved and no reply.
Even though app is the only way of communication but very conveniently they decided to not answer. I found this is very unprofessional and really wonder there business model without strong customer support.