Hitachi Ac - No service given

I have bought Hitachi Split Ac last summer on ** June **** and it's still under warranty. I called them several times for service last year but no one turned up. Now in starting of summers, I called these guys again for the service this time their serviceman turned up and told me AC is not working after checking it out he said one of the parts is not working in the outdoor unit so it will be replaced. It has been more than a week he did not come back. As per him part is not available in stock and will be replaced once it's available. It means I have to wait in summers for these guys to receive the product. Do they guys realize how unprofessional they are? Worst is their customer service team they don't have any TAT or they say every time have ** hrs TAT but no response. I have made a big mistake in my life buying Hitachi product I would never recommend such a third class product to anyone. Such cheap product used that it got defected in only within one year that's only when operated for * months.