If you just dump everything in and don't follow the machine instructions for whatever machine you have no wonder you haven't had one to bake right! Some want the liquids first (most) and at a certain temperature range. others may have a different order.
Bread flour IS different than regular flour and while you can use regular flour, using bread flour does make a difference. You can buy either at the grocery store these days.
There should be adjustments for altitude and you should be able to bake a loaf at high altitude. I am sure there are people who live high in the mountains that have used the machines and perhaps they can help you with the adjustments that need to be made.
I have found if all else fails, READ and FOLLOW the instructions given and after you have mastered those, then deviate and experiment from time to time. Bread machine yeast is a faster rising yeast than regular yeast and compensates for the shorter times with the bread machine.
My two cents for the day!