I have nothing but contempt for Big 4 firms when they do this (they did it to me too). For a bunch of firms that claim they train the very best, it's amazing how much easier it is to get sacked for failing an exam than poor performance or gross misconduct. Here's a list of things people didn't get sacked for in my office:
1) Turning up at least 15 minutes late every day for the entire training contract;
2) Regular outings to the pub at lunchtimes, turning up at an audit client's offices in the afternoon worse for wear;
3) 'Phantom' ticking and testing found to be deeply flawed or unsubstantiated under review;
4) Taking Class A drugs at a firm Christmas party;
5) Glassing a colleague, who subsequently left the firm (the partner helped move some money around to prevent a criminal conviction for that one - the guilty person is a director there now);
6) Being convicted for driving without insurance.
You could do all those things at my firm, but don't you dare fail an exam! I suspect it was because exam fails were dealt with centrally, whilst misconduct and poor performance was dealt with by the local firm, who didn't want to sack anyone for anything (not an ideal model).
As for next steps, I'd first work on passing what is presumably the last module of the CFAB in your own time. I would have thought one of the top 20 chartered accountancy firms would want to take you on but your timing is unfortunately not great. Most firms will begin sorting out training contracts for Sept 2015 in the next couple of months and spaces for 2014 will already be taken so I suspect firms will want to take you on but don't have the headcount this year. However, the good news is that some training contracts start in January, which won't be such a long wait.
When I was in your shoes, I decided audit wasn't for me anyway and went and did ICSA and worked in Fund Administration. Now I work in Compliance and I haven't looked back. However, I do acknowledge that I would probably earn more if I had the ACA and in your shoes I would say go to those top 20s and apply for their training contracts. I'm fairly confident that you will secure one, at least after passing that bad fail exam.
In the meantime, you also need to work and what you do really depends on how long you have to wait to get back on a training contract. If it's four months I would swallow your pride and do whatever you can for four months; earning is always better than being unemployed. If it's a year, I would try and find a bookkeeping or admin job.