Quality Issue with Nissan Sunny (from owner)

I had purchased Nissan Sunny Diesel in Apr 2012 after returning from the USA. I bought the car after considering the good reputation of Nissan and a long wait period of Suzuki Dzire. I have got all services done at Nissan dealers. I was surprised when suddenly the cabin heat function stopped working in early 2015 (AC was working fine). I took the car to the dealer in Oct 2015. He advised to change some part which he did not have. I finally got the part changed in Dec 2015. The issue recurred in Jan 2017. Not both AC and heat are working at less than 50% capacity. The dealer is not sure what is the issue and has advised HVAC service. My personal opinion is that on should not buy this vehicle due to quality issues. On top of that, their customer service is pathetic and as some people have written in reviews, the dealers do not stock adequate spare parts, causing you to make multiple trips to the dealer for service. Overall a very costly car from a maintenance perspective. Hence, one should stick to Suzuki or Hyundai cars only in India!