Who does code written by myself during a partnership belong to in the event the product is later "acquired" by the other party's company?

I was approached to do a re-skin of my work for 50/50. I agreed and continued to develop this new product. A third party joined and we agreed to 33.3% each. This new partner incorporated the product under their company - without my knowledge. Now they bought the other founder - again without my knowledge - to own 66.6% and changed all product credentials - also without my knowledge. They're now trying to buy me out and insist I sign to transfer all IP, an NDA and a no-compete. However their document seems highly formatted in favor of taking even work that the product is based on and their noncompete is so vague - it almost seems hostile. They also insist that they already own all code developed for the product since the product is now owned by their company and that signing is just a formality. PS. There has been no contract of any form.