Timing Tensioner problems of the 2009 Mercedes Benz C300

Last week took vehicle to get serviced at Mercedes Benz of beverly hills. When I got it back I heard a whistling/flapping noise. Immediately returned to mercedes service. Was told its nothing of concern if the noise only happens in the mornings and dissipates when driving. Expressed concern about a 1100 mile road trip ahead and wanted to make sure it was safe to drive. Was reassured it was just fine. Upon arriving at my destination the noise escalated non-stop come to find out it was the belt tensioner on my vehicle. The serpentine belt was nearly shredded. The vehicle had about 70,000 miles on it. After doing some quick search online, it seems that this is not an isolated issue, but rather a widespread issue with this vehicle. I'm pissed that the service advisor played stupid as if this was not a known widespread issue and put my safety at risk. I've read some owners have had this failure with as little as 15,000 miles and so forth. Mercedes is a fraud and are well aware of these issues they just hope its not apparent while the vehicle is still under warranty.

Noise coming from front of engine. Brought to a local Mercedes Benz independent shop. They replaced the belt tensioner, idler pulleys, and the multi rib belt. Why would the belt tensioner cause the rib belt to rip with only 62k miles on the car?.