If the coaster brake assembly was properly installed, serviced with good quality hi-temp grease and everything was properly adjusted, the only way that I can think the axle might bend is if the coaster brake were slammed really hard. I honestly don't know if that even would bend the axle or not, I just can't think of anything else that would cause it other than something not being properly adjusted. Coaster brakes are very widely used on bicycles, and have been around for a long time. They do require more attention and maintenance than other types of hub, especially in a motorized application. But bending two axles is nothing to do with your weight, height or the design of the hub. Sorry, but you're blaming your bad experience on a part that's not known to fail at all. If others had had this problem as well, then it would certainly be a possibility. But what we have here is an isolated incident with the person that had the bad experience making a subjective claim of faulty parts, and plenty of evidence to the contrary. So far, no one who has commented is accepting the explanation that is being given. The scary part is that if you don't know or care what actually went wrong, you are very likely to blame almost every problem you have on the parts that fail, and in my opinion that is going to come back to haunt you. You'll do something wrong one day and not realize it, and it will cause you or someone else a serious injury. I'm not trying to diss you, bro. There is just something about the attitude of automatically blaming a failure on a part without trying to figure out what actually went wrong that bothers me. Especially when evidence to the contrary is ignored.