Ignition & control module on 1999 e-320

help!!! a few weeks ago, my car wouldn’t start, altho made noise of trying to. had it towed to dealer, who installed a new ignition system. $1729. when i went to pick it up, it wouldn’t start! dealer kept car a few more days, then, when i went to pick it up again, said it prob. would never start right away, that i should keep trying, including new key and old key from previous ignition. a couple of weeks later, the car wouldn’t start at all; just made a soft click. when i eventually got it to the dealer, they said it now needed a new controle module, for another $1600. wtf???