Wow! These are not typical like replacing your J pins. My trailer was about 9K lbs with a 10K hitch and 1K bars and did great. I can not imagine why this would have happened unless you have adjusted too much weight on the spring bars.
Here are instructions for adjusting and troubleshooting
http://www.equalizerhitch.com/pdf/EQOwnersManual.pdf
According to the troubleshooting on page 25, the brackets may have been too far back from the ball.
If the brackets are too far, there would be excessive leverage and pressure. I hope this may help. Problems are often in the subtle details of the set up. Good luck.