Ml 350-irreparable factory deficiency

Warning advice to all of you who intend to buy a ML 350 manufactured in US. It may have an irreparable factory deficiency which drains dead your battery, unexpectedly, about 5 times per year. The only way you can start it over is to call service pick-up and have it reset in Service . Although the car has been investigated and serviced in accredited Mercedes services more than 20 times within the last 5 years, they could never find and solve the problem. Even more disappointing is the fact that although I escalated it at Mercedes-Benz USA, at the level of Regional Case Manager, they did not assume any responsibility and rejected with indifference any assistance, replacement or compensation as it was out of the 2 year warranty.
Meanwhile, if any of you have the knowledge how I could turn this around, please let me know, your advice would be greatly appreciated!