Nokia used to have some unlock code calculators that one could find online. I believe it was the only company to have that available. You could try to find one and apply it. Beware, you can only input the subsidy code wrongly only so many times, so if you don't know it, don't do it. Unfortunately, no one can just "figure out" the code. It has to be calculated using an algorithm.
Looks like this topic got stuck after my message got quoted in a reply that was deleted afterwards. mods, please close the thread.