Apple Support fails

Over the past 12 months I had and still have various product hardware and software issues with one case not been resolved in over half a year. I call Apple Support, talk to first level advisors who pretty quickly connect me with a Senior Advisor. All of the SA's said they take ownership of my case. We go into the issue I have, send requested information like screenshots, video capture, diagnostics etc. and then the advisor says and promises he/she will contact me via email or a call back within 2-3 working days with an update from their (engineering) team. Some advisors did but only once and then I never heard from them again. They just dropped me and their ownership went up in smoke. We customers shall not take this Apple post sales service attitude and their should be a way which I haven't found yet (if there is any in the first place) to get hold of the advisor or the Customer Relationship Manager to file a complaint. I am by far not the only one who spends thousands of dollars on Apple products and then when it comes to issues that require a fix I get dumped. I can provide case ids with names of advisors if someone wants to have a look into this. Something is very wrong with Apple here and that calls for rectification.