Have you been working with her, so she's ready and willing to have a stranger pick her hooves up and do things to them?
If not, the farrier who's too busy to come, may refuse to work on her once he gets to your farm.
I would also call local vets (including small animal) to see if they know of other farriers or barefoot trimmers in the area. One of the top farriers in my area is married to one of the vets where I take my dogs and cats, for example.
I would also call area boarding barns and training facilities - even if they are 50 miles away. When I first moved to TN, my shoer lived 30 miles away but had clients up to 100 miles away in the next state.
There's more than one person around to trim your horse's hooves - it's just a matter of digging deep and doing some good detective work
In the meantime, work work work with her hooves so she's not a nutcase when somebody does show up