The former officer and aditional former director both resigned with intention to take over the company, they failed and I'm confident they've set up a new entity in violation on the non-compete and they are not using their own names. The new entity is probably registered and operated by unknown person to me. If they legaly can just ignore my demand letter, the only way to find out what they are doing is by filing a law suit?
During a lawsuit, they would have to respond to discovery requests by providing documents and information. But before that, you may want to do some investigation on your own---on the internet, asking around among people in the business (competitors, customers, etc.), checking various public records for any business filings, etc. An attorney can help do those things as well, particular in searching public records or hiring a reputable private investigator.