Suspension Noise problems of the 2003 Mercedes Benz S Class

My suspension is horrible!! without warning my s430 airmatic light displayed "visit workshop", I pulled over and noticed my vehicle was riding extremely low. . . Almost touching my front and back tires. Furthermore, there is a rubbing sound when the wheels are being turned. I contacted 4 dealers and they all claimed the suspension and/or airmatic system has been a common problem . . . My concern is why wasn't I notified about a recall? secondly, after scheduling an appointment for this week, mb is claiming that I will be charged for service a. This is unbelievable>>>why is mercedes loosing their reputation for poor customer service? please contact me. . . I need my vehicle in operable condition and will expect to be reimbursed by mercedes once this recall matter is approved and/or active. I'm glad to know that NHTSA cares. . . Thank you.