Rear Suspension Springs problems of the 2007 Volvo V70

This car has been driven with care for 7 years. It has never been in an accident nor has it had other significant failures. In the past few months both springs on the rear of the car have broken and the car has dropped significantly. We repaired the first one ($500) and were told that the dealer (wynn Volvo) has never seen broken springs until this year. When the second one went today ( while in the driveway) it not only raised concerns about the quality of the vehicle, but also about the safety of it. If we had been driving at any speed when this happened, serious injury and potentially death may have occurred. In doing some research, it appears that this is a recurrent theme with Volvos during the last decade. It seems that there is inherent danger that could cause injury or loss of life and yet Volvo claims that it is not common. I disagree and would encourage an investigation.