I don't know the company you are dealing with, but it looks like they are changing a lot of expensive parts in the hope of fixing a problem. I hope you have a full maintenance contract, one where the company absorbs the cost for a monthly fee. It seems like a competent adjuster should be able to isolate and fix a specific problem, and not just throw parts at your expense to see if something sticks. Unionized Elevator Companies have Techs that go through lengthy Apprentice Programs and ongoing training. I would make sure you are dealing with a reputable elevator company. This thing has a smell about it.