Car doesn't have power when you first start it

I took my car to Hyundai workshop in Pinetown as I purchased my car from them on 14 Feb 2017. I was happy with but recently it has been giving problems. It has no power when you first start it and when I turn, it sometimes makes a "click" sound. The gentleman in charge, Donovan, said it didn't give problems when you start it. But that isn't the problem. The problem is when you first start it and you have to drive in 1st gear for about 500m, only then you can go faster. I'm very unhappy as my car is still not fix and it's still under warranty. It never gave these problems when I first got it. Why didn't he put it on the machine to test it? I'm very dissapointed and I won't recommend anyone to go there.