Hi Silver Rose, sorry to hear about the trouble you are having with your buttonholes. One other way you can do these is by making bound buttonholes, they really are easy to sew and look superb. I first learnt how to do these when I was still at school.
In addition to what Ploshkin has mentioned, i.e. the Humper Jumper, there is also another similar gadget called Jean-a-ma-jig which does the same sort of thing. Not knowing what your machine is why not pop into Franklin's and see what they have, you never know there may be a special accessory for your particular make of machine. If by chance you have a Bernina, Bernina do a tool that is specifically for doing buttonholes on thicker than normal fabrics, especially when you have the facing seam, so it might be worth exploring what Franklin's have. It is a very long time since I was in that shop - in fact my mother bought her Bernina from there way back in 1975 - I now have this machine.