Airtel — no response to corporate customer care email or helpline

I am the coordinator for my company and i have been trying to raise a complain regarding improper billing for the past 1 month. Last month i paid the bill despite the error since the amount was small and i did not want to be late and hoping it will be eventually looked into and reversed the following month. This month i got an even bigger error in billing and after multiple emails, i have no reply and the bill due date has passed. I am unwilling to pay until someone responds to my query and reverses the error but until now, i have not been able to speak to anyone who can do this. 121 say they cannot help becuase its a corporate connection. And corporate email helpline does not reply!