That’s a different issue – what that means is where there is a mediation, the parties attending must have the authority to agree to any settlement/terms that are agreed.
If someone applies for a mediation the other party can decline to attend. Refer here:
The mediation step is because you can’t apply to the CTTT for an adjudication unless you have done that. The way it works is you apply for mediation, the mediation occurs or does not occur (if the other party declines to attend), if no resolution is reached then you can apply for adjudication. The advice given to you by the OFT was correct to that extent.
So now you can go ahead and apply for adjudication, you just need to attach evidence that you did the mediation step which I believe is the advice that the other party declined and the file has been closed.