Not the first account of broken springs on an RV. Properly made and sized this should never happen. When we had our Holiday Rambler the subject caused me to inspect the axles, springs etc. It was 2002 model. Everything was fine. But getting the units out the door was/ is first quality is second on many models. I'm surprised as injury, death, destroyed RV and Tow Vehicle and lawsuits is probably a consequence, in some cases. Ours had shocks which stops a lot of motion and keeps dishes in the cupboard, and springs in perhaps violent rebound.
I don't know if yours has shocks, but suspect most new ones now do. If you determine the spring broke of its own accord replace them all with American springs. ...and put on shock mounting kits. We sue to have a spring shop in the next city over, and they could calculate what the spring rate and spring was needed and build sets themselves. The shackles may need replacing, with larger ones requiring welding perhaps...and use urethane bushings instead of rubber. On our Motor home the rubber bushings on the sway bar were destroyed in no time.
When we unpacked the coach, I estimate at least a thousand pounds of stuff accumulated over the years.Add a thousand or more to your RV weight on the plate, and you may want to change wheels and tires too. We did.