BRAND NEW CAR ISSUE UNRESOLVED

I brought a Kwid dynamic 1.0l 2019 model at the end of July, within 2 weeks a warning light had appeared and the manual had advised to take it into the dealership, which i did. it is now the middle of October and other then being told a technician was due to come and inspect the car and the fault is unknown, I have literally had zero feedback. The sales person calls me know and then to check the K's on the rental they have leant me but hen asked whats actually happening with me BRAND NEW car he is so blase' and says someone will get in touch and that no one knows what the problem is because its "rare" so now I wait in limbo. Who wants a car back with an issue when its brand new, and the fact that the after service from Renault sucks doesnt really help the situation. I honestly wish i had never gone to Renault in the first place!