Dewalt DC820 18 V Impact Driver Wrench,2nd one,going for a 3rd?

I bought a new De Walt 18volt 1/2″ drive model DC820 new style head (3). It broke while trying to loosening a 5/8 nut. It took 7 ea. 5/8″ nuts before it quit turning on the drive head, the motor still turns in both directions. I ship it back to where I purchase it from. I got another one back from the same company in 2 days, fast service. I took the new 2nd driver impact to remove the same nuts and it broke again in the same place of the drive head, just like the 1st one that I purchase from the company. I will not buy another newer model DC820 from De walt until they fix the problem, I will look around for the older model that has the 4 screws on the head that is removable, compared to the new style that had no bolts to remove it from the head. De walt you have a design problem and I am not going to waste my time on the 3rd set, please fix the problem before you put out the newer versions, looks pretty, but no reliable.