It seems like it is time for you to hire an experienced criminal defense lawyer familiar with the court in which your case is filed. Just because the accuser got the money back doesn't erase the act.
If the other party is not cooperating with you, there is not too much you can do. If they are angry with you, it seems to make sense to get someone else to try to speak on your behalf. Hence, hire a criminal defense lawyer.
That being said, the best chance you have of resolving this matter successfully would be to hire a lawyer to negotiate with the prosecutor to see what, if anything, can be done at this point.
If the District Attorney has already filed charges for Grand Theft, the fact the complaining party has received the money in full should play a large part in a more favorable sentence if convicted, and possibly a reduced charge plea bargain. Assuming the aggrieved party would ever be ok with a Civil Compromise, there's a chance the case could go away completely.
Only the prosecutor's office can file charges, not the person from whom the money was taken. Theft depends on the intent of the taker at the time of the taking. If the intent was to return the money, that's one thing, if it was to take and keep the money, it is another thing. The surrounding circumstantial evidence usually points in one direction or another.
Get a good lawyer, whether that is a public defender, or a privately retained lawyer. Many private lawyers will be happy to consult with you by phone, at no charge. I suggest you make some calls.