Voltas — complaining about my split ac water leakage from the day of purchase.

Air/ mam, ive bought voltas split ac last year february. After first free service, water leakage problem stil exists. The mechanics four times serviced it. Even on 11th feb, mechanic took the ac for service to their centre telling me that v should change the coil and it's free of cost for warranty exists. After 15 days they reinstalled it. They told me they changed the coil but later the service centre receptionist told me they r waiting for the coil. Once v received, wil rectify the problem. But it doesn't happen. Stil the water leakage problem exist. Day before yesterday on 30rd august, again i raised request for water leakage through watsapp. Mechanic came on 3rd september did something and charged me 500. For service request. I'm much depressed in this issue and the service made by u. Suggest me what to do.