No Feedack of Factory faults

My Wife bought a GWM M4 in December 2015.They promised us that we will have our license plates in early January of 2016.Still today no phone call or even if I phone them the have problems. The same day we bought the vehicle we noticed a fine hairline crack in the speedometer glass and requested it to be fixed. We reported it the same day we bought it and the sales consultant that is not working there anymore promised he will let the manager know about it . I took the vehicle to show the GWM staff the crack in the speedometer glass and they said they will fix it also the door handle was loose and the service manager said it will be an easy fix and they will do it. Till today no word of it yet and after numerous calls no answer on the matter. Two weeks after we bought the vehicle we noticed something else is wrong with the vehicle if you turn left the vehicles mechanical power just dies and the vehicle comes to a almost complete stop and corrects itself if the steering is turned back.I need this sorted out asap and is very upset wrt the service from them.If this is not settled I will give the vehicle back and I will involve my lawyer in this matter.