What can we do to force a home health agency to follow Mom's wound care doctor's orders?

We've battled this issue for 10 months! Mom has Parkinson's and dementia but her main problem is a large decubitus ulcer on her sacrum. She is at home and we've battled this since February. We've gone through 3 home health agencies and had the same problem with them all. Poor wound care by them, with dressings not staying on, improper dressings applied, etc. and then they blame us.
Now the current agency wants to discharge her from their care because her wound isn't healing. They claim Medicare won't continue paying them for care or assessment. However, she has a Foley and another hip wound that IS improving. No one seems to be able to get them to properly follow a care plan.
Hospice is a choice, but she has a fluidized pressure-free bed that keeps her from developing more sores and she would lose that if hospice took over. So, that's not really a choice, after all.
It's very frustrating because I've been a paramedic for many years and have always done whatever was best for my patients, and now I'm dealing with "health" agencies who worry more about money than care!