Gears not engaging on a brand-new car - 1 year old

I regret my decision of buying a Renault as a second car. The car is barely 1 year old, but I experience power failure. gears couldn't engage, became worse on an incline. I dragged the car to Renault only to be told without proper diagnosis by the manager that "it must be a problem with your driving" I told the guy I have been driving for more than 10years with no issues. the car is barely 1 year old already power failure. Customer service is terrible. I regret my decision of buying a Renault Kiger. never ever will I buy or recommend someone to buy a Renault ever again!!