The situation with intellectual property/copyright is that it endures for 70 years beyond the death of the originator.
It vests in the originator/author regardless of whether the originator/author was paid for the work or not and provided there was no agreement that it would vest in who commissioned the work.
If the originator/author was an employee (which you say you were not) then the intellectual property/copyright vests in the employer.
Hence, from what you have said, the IP/copyright belongs to you and you can do with it what you like. If you wanted to sell it to the big wide world, you could.
You were paid from January to August 2015 and the company that paid you is entitled to some kind of benefit for that payment. What that benefit would be would depend on the nature of the agreement between you for you to do the work on them to pay you.
There is a legal doctrine called Promissory Estoppel and if you were promised something (directorship) and you relied on that promise to your detriment (did work) then you can enforce the promise although in practical terms, becoming a director of a company that doesn’t actually want you is not going to be a particularly good idea.
Can I clarify anything for you?
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