Videocon Industries — Air conditioners poor customer care

3 months before, 2 executives visited my home to check problem in videocon ac, they found some issue in outer unit. They removed circuit board and took along that for further investigation. In 2 weeks, they confirmed, issue is with circuit board, they will replace.
On 11th August, they confirmed part is approved. But today after 2.5 months also, we haven't got any part and nobody visited. Whenever calling customer care, they says they don't know about fixed timeline but you'll get soon. Even they can't confirm whether we will get in two months or 6 months.
I don't know where to complaint and how to raise further.
Complaint mobile number is [protected]
Alternative [protected]