Assuming that (a) the events that transpired created an oral operating agreement for the LLC (certain provisions of which were to be memorialized in writing) and (b) the investor / majority member has been acting as the LLC's manager, that member owes the LLC and the other members the duty of loyalty and the duty of care.
If you want a more-specific answer, you will need to retain a business lawyer to examine all of the relevant facts and documents and render an opinion.
This information does not constitute legal advice and does not establish an attorney-client relationship.
You need to hire a lawyer who can advise you as to how to proceed. For example, were you an employee? Owner? Did he represent things to you and not fulfill his promises while you took action? You could have a breach of contract or quantum merit case. Those are just examples. You would have to meet with a lawyer who can review the facts with you.
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It seems quire clear that you need the services of a business litigator. Assemble all the emails and any other documents, reduce the "history" to writing for easier review and consult an attorney. I am handling two of these matters right now. It is not uncommon.
The above is general legal and business analysis. It is not "legal advice" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.