Scrivener blackmailing – Changing representative is not possible?

Hello everyone, I am waiting for a business manager visa requested 6 months ago through an administrative scrivener.

I am having serious problems with my actual representative, as she is not acting in a professional way, not sending documentation and not notifying me about anything. She's the only one with access to my money and she's blackmailing me.

I have already asked another lawyer who wanted to help me but he phoned Osaka Regional Immigration Bureau and thay say I may not change the agent at this stage because it would mean to start from the beginning with a copletely NEW re- application

I feel really vulnerable and completely helpless… as this scrivener is acting just against my interests, only creating problems and now blackmailing me.

Anyone has had a similar problem? Is there anything I can do?
Please, I would need some help.