Home assessment no show...

I urgently need advice. The atos HP missed her 2 hour window and after my dad called atos, she conveniently called 2 minutes later to say her car broke down, was waiting for her breakdown company and didn't know how long or if she'll make it. She said she is 40 minutes away but even if her car hadn't broken down, she never would have made it to my house anywhere near the end of the 2 hour window. I've taken a day off work, have been in a complete state all week worrying about this and have been a wreck this morning, I can't go through this again. Atos have just said they've not heard from her and to either rebook or see if she turns up.
I'm fuming because I supplied mountains of evidence, a very detailed form (using the wonderful guides found here) and supplied supporting letters from my neurologist, employers and an occupational health report from work.
They have not contacted a single one of my doctors or physio and I left no stone unturned so why they need to see me I don't know.
What I really need to know is what do I do and where do I go from here? I'm shattered and it was very difficult to get the time off work for today.

Any advice greatly appreciated!

Thank you Gordon

She did not turn up. I ended up having a panic attack and having to go to an emergency gp appointment.

My dad is drafting a complaint email as we speak. I've been told I have a new appointment next Tuesday. Thank you for your advice, it is very much appreciated.

Claire