cheated by lawyer

A lawyer's fee can be fixed by the lawyer only and not by the client, if you cannot pay, change the lawyer.

This is common practice to suck money from clients.  Either change lawyer or if you cannot afford any lawyer.. then become a lawyer for your own case.  As the matter is just family based case, no need to appoint lawyer too.  Many people who are fed up with such practices of advocates, handle their cases themselves with little help from those who have already dealt with their cases on their own.

I am not familiar with Mumbai but in general and especially in Delhi where my litigation took place, I have always expressed my opinion that advocates are basically the reincarnations of the devil with just one difference - their IQ which is usually in the single digit. I belong to the medical fraternity and have always looked down at advocates as creatures who provide evidence of a gap in the evolution of the human race. I have a lot of respect for other professions, especially teachers, who may just be BA pass or a chaprasi who may not have any education. But LLB, only idiots pursue it. That said...

Did you pay your fees in cash? If so, there is nothing you can do unless you have a valid receipt from her. Otherwise, it is her word against yours.  But you still have options. Tell her that if she withdraws now, you will file a complaint against her with the Bar Council. There must be a Bar Council office in Mumbai or some other city close by. There usually is one for each state. If she does not show up on the last day, then that is exactly what you must do. However, in litigation, threat is sometimes better than attack. So, do not rush into filing a Bar Council complaint. Let her have the sword dangling on her for some time. May be she will change her mind. Also, tell her if she compromises your case, you will do the same thing and also file a civil suit against her for damages, which you can do if she does something fraudulent.

Advocates in general are cowards. If you go on the offensive, they will crumble fast. Keep this in mind. Worst case, ask for an adjournment in your case seeking resolution of a dispute with your advocate. Then file a disciplinary complaint with the Bar Council.