Engine problem within 25000km

I bought the xm diesel in march -2018.from that onwards I faced a lot of issues regarding their service. Three times i faced ac complaints but they charged always 3500 in every time. But still the problem is continuing. Now my car crossing 25000km. What are the problems are faced up to till date I clearly explaining 1, repeated ac problems. Problem is not resolved. 2.very poor paint quality. Previously i used Maruthi car am not facing these issues. In bonnet side in corner end near in glass side. It is rusted. reg this am asking the service manager. He said u should use pure water.i really disappointed. I maintained neat and clean in my car always. Every tiny maintenance I did showroom only. I really upset that the service manager gives the cheapest answer. 3.then finally i decided to plan another new car. When i going to sell this car. The party asking very cheapest price. If I sell this car for foreclosing purpose i need to pay extra 1laks. So it is a high loss. 4.then crossing 2years now car 25000km. On the date nov-2-2020 while am driving the car, some noise found from the engine side. So suddenly i take off my car in near showroom in Tuticorin, susee auto pvt ltd. They said noise came from engine side we should dismantle this then only we give the estimation. while am buying this car i added additionally extended warranty. So I asking for claimed they said we send the quotation for approval. So he said to wait for some days. Now one week crossing one week. Still pending. Then they said, we try our best for a free claim. Then i shocked, am asking them, boss, I have an additional warranty then u said we will try. What is this and fighting with them up to till date. Complaints -crankshaft bearing damaged. The crankshaft is slightly worn out. So finally i request to all, don't buy tata product specially tata nexon xm diesel. Best go for Maruthi and Hyundai. Now am booking i20. So dont go for tata brand.