Rear Suspension Shock Absorber problems of the 1997 Subaru Legacy

I installed mevotech strut mounts (mp903987 & mp903986) on our 1997 Subaru Legacy postal when installing new rear shock absorber/struts. The right side failed on the first day after around 60 miles. I replaced it with the original factory part that had lasted 420,000 miles. The left side failed the next day after being in service for approximately 100 miles total. I returned the other original part to service. The failures allowed the strut to push through the mount and hit on the thin retaining plate. It allowed the rear suspension to become extremely loud and loose. I reported this to the manufacturer and received no response. I reported it to the seller, rockauto, and their response was that I should do more research on part quality. I believe there is a difference between poor quality and dangerous defect. I have the faulty mevotech parts in their original boxes.