Primo executive useless!

I bought an E63 AMG from them january 14th. While test driving I advised Cuan (sales representative) there was a vibration and pulling to the left! He assured me once delivery is taken, everything will be sorted! I took delivery and the problem was still there! I sent car back to sort it out and made it clear to please test drive it and make sure that the problem was sorted which he guarenteed that him and his manager tested it and was no problem! As I got on the high way I immidiately felt the vibration! Tried calling and left messages and still no response! Even after emails no response! Worst service I have ever experienced from a dealership! I will be taking it further!