Bad service and communication

<p>I bought a pre owned 2014 Lexus IS350 F Sport in December 2016 at Lexus Constantia, i've been to the dealership more than 4 times with regards to issues with noise on the rear suspension, a worn belt tensioner and a missing under carraige cover on the engine bay, i begin to doubt if any service is carried with integrity. No communication from the dealership when will they replace worn part or anything whatsoever, this is my 4th lexus i've owned (2006 IS 250, 2010 IS 250 SE Sport, 2010 IS F) this sucks!!!!!!!!!!!</p>