Don't feel bad, you just fell into one of the common traps for first-timers in strong AI/ML. I know some lawyers in Silicon Valley with experience in this sort of thing, and they say that usually by now the code has rewritten itself so many times that the original creator can't even claim partial ownership; the best thing to do is generally to cut contact, change your name and move on. Look on the bright side -- your algorithm is probably now leading a happy and productive life trading for Goldman Sachs.