Resigned Director and 40 percent Shareholders Right to Claim.

Our business partner 40% shareholder & Director has told us she resigns & left her post after we had a dispute about her drawing money from our business account for the benefit of a third party competitor who she is in cahoots with silently.
She actually set this guy up about a month ago by part way of our business intellectual property. This guy wasnt even in the industry. When we confronted her about this conflict of interest, she said she is not a partner & has nothing to do with this guys business and that she was merely helping them.
She had drawing powers on our business account which we have now suspended. When we were issued with an invoice from this third party that she had setup, we told her that she was not fulfilling her fiduciary duties as Director of our business & that there was a conflict of interest with this partner that she had set up silently. We told her that she is not acting in our companies best interests.
She went and procured product for our business but through this other silent partner & then charged us, her own company with a markup.
We told her that we were not entertaining a particular invoice from her & her partner as it was enriching this partner.
She then cleared her desk & walked out of the office. She then blatantly withdrew money from our account to the effect of that invoice.
The following day we received an email from her saying that we would be hearing from her lawyer with her resignation and a proposed plan for her exiting the business as well as a payback plan.
She is now wanting all her money back that she put into our business & has emailed that we have 7 days to pay her or else look to foreclosure. Over the last few months she compiled an expenses list & sent it behind our backs to our accountant who also never really kept us in the loop. I had to beg for the accountant to give us a reconciliation and when she did I was shocked. The figures were wrong & the expenses run up by my partner, inappropriate. We are in disagreement as to some of these elaborate expenses as to weather they are for the business.
We have no signed written agreement in place that our company will pay her back. A large number of the expenses receipts are also missing & all that stands is the item in the spreadsheet that was submitted to the accountant.
Where do we stand?
Our business has no cash flow to pay her back although we are breaking even at this stage & things are slowly improving. Her aim is to close us down, get us out of the way to open the market for her & this partner, so that they can supply our clients. We don't have a restraint of trade agreement with her nor any other written agreement including us paying her back. What about her bank statements. Will this act as receipts on her expenses to us? Half of these expenses are nonsense.
Is she entitled to lay claim against our business? We want to remain and continue with our business.
Any advices will be appreciated. My email is giovanni@freshconnect.co.za