2008 Mazda 3 suspension issues.

Heavy clunking from all four corners of car when going over any type of bump. Dealer inspected and told me that driver rear coil spring is broke and passenger rear coil spring is almost broke. Stated there was oily residue on shocks so possible shocks on the way out. Just replaced the shocks about a year ago. They did not say anything about front end. I asked about sway bar end bushings and they didn't even give me an answer. Notice no oil residue in driveway like last time the rear shocks went and when I push up and down on rear of car the car rebounds like normal with no excessive up and down motion