Capita ended by assessment due to error on laptop

Hello, has anyone got advice on how to go forward with this. My telephone assessment lasted just over an hour when the phone went silent and then cut off. It was recorded. The assessor then phoned back and said her laptop had come up with an error and so she could not continue. Upon phoning Capita, as advised, they have scheduled me in for another assessment.
I'm not happy with this. I gave a significant amount of information. I also had to use my work's assistive software, which strictly speaking I shouldn't be doing, to take part in the assessment but I had no choice after Capita declined giving the questions in writing before the telephone assessment. I've already complained to them no response yet. They've suggested complaining again but they won't reply before a new assessment. Any advice on what I can do beyond this?