We don't mean inexperienced in general, but the vet is clearly inexperienced with chameleons.
I'm not sure if you completely realize the seriousness of the situation. Your chameleon might not die tomorrow or even this month, but the illness that she has is causing her immense pain. Her legs are either already broken or they are in the process of breaking. She will not be able to dig, and if she tries, don't let her. Dig her a hole at an angle and set her in it and see if she uses it. If she doesn't lay soon, being egg bound will kill her before the MBD ever does, and dying from that is very painful in itself for them. She is probably in added pain or discomfort from being egg bound.
I know you want to do what is best or else you wouldn't have taken her in to see a vet, but either way, please trust us a little more on this. I have only taken care of a chameleon for a year, but some of these people have been at it for a long time.
As I mentioned before, my chameleon had MBD from her previous owner. She cannot close her mouth because her jaw is bowed down, one of her back legs is in the shape of a 'S', her two front legs are bowed out and double jointed, and she has lost the ability to use her tongue completely so that I have to hand feed her every night. MBD just doesn't go away, and it just doesn't happen suddenly. It is going to take her a while before you start seeing improvements, so the sooner you make the necessary changes the better.
Please look back to the first page at the list of corrections that were given to you to make. Some of them, like the supplement issue, contributed to her current condition.
I know a lot of this was blunt, but you have to understand, not only am I biased, but I hate hearing about animals in pain. I don't think that you are a bad owner at all, on the contrary, but a few changes needed to be made in your husbandry to ensure that this doesn't happen again.
And, correct me if I'm wrong someone, but I think that chameleons don't eat very much right before they are about to lay. She probably doesn't care about food at all at this point.