Hi, some help for your bag.
The vertical bolt that keeps unscrewing should be longer. Replace it. Then add an extra nut, so that you have two nuts right next to each other. Tighten them so that they lock together.
If the horizontal bolt breaks, replace it with a thicker one. You might want to try a bolt with an "eye" on the end. This requires some changes in your gear of course. Please see this photo from the dojo where I train. This is a large bag for both kicking and punching. Very solid construction.
