Try and do some research on Obs that are supportive of VBACs where you live, they are more likely to be on your side.
Approach them and tell them your story including the part about your current Ob telling you that you must have a c/s and that you aren't comfortable with that decision. Even though it can be hard to get on to their books initially, they often have 'spots' for higher-risk patients which you could probably squeeze in to because of the situation. Doesn't hurt to ask.

Good luck hun!