Poor Aftersales Service

I bought a Mitsubishi a year + ago as I was sold by the salesman on the service, he even collect me from home when I was to receive my car, but the aftersales regretfully was woeful, not my first but second service, I decided after my the second service I never want to experience such again and , today I took my vehicle for a trade in and to my shame found out my service book was never stamped, I went back to the service center and dealership at Hyundai/Mitsubishi Centurion and was directed to ''Otto'' the Manager in , charge, a welcome greeting only at first, firstly Mr Otto, always ask a client to have a seat, it is polite, don't raise your voice, even if you are not at fault, correct them in a polite manner, if you are not the man to deal with the situation , teach your staff to direct the clientele in the right direction, don't vent your frustration, finally thank you for walking me to the person to assist me with a problem that ,TWO SERVICE DELAERSHIPS overlooked ,clearly it is an internal problem which two managers cannot see. Same situation in that office a welcome greeting, no need to offer a seat at any point to the client standing in front of you?? A beautiful car with pathetic aftersales service, I will not touch a Hyundai or Mitsubishi in my lifetime again and will market this ideology to family and friends. Maybe a change of management is needed to see change. At no point did any of these MANAGERS request my name - thank you for at least calling me Sir. it is appreciated. I do wish you success in your business. I so appreciated the great service again.