Your comments are noted and perhaps you should learn that it is best to just ask for the dealers advice on an upgrade. Ask him to confirm what work he recommends and give you a written quotation for doing the job.
Once you start specifying what you want you are taking some responsibility for the outcome.
I have found that there is usually a local small dealer who is concerned to give good service and keep his valued customers. Find one.
Your experience is not unique, unfortunately.