I estimated X hours. As I showed them the progress, they started adding more things to do that was outside what was expected or was not portrayed in the beginning.
I asked for 50% of the original estimate (tiny budget) but they want all the features that was added along the way until even half of the agreed upon payment that was supposed to have been made earlier on.
I thought if they can't even pay 50% of the budget when I reached alpha stage, and that they are wanting all these extra features, I simply must bill them for more. I billed them for another X hours including the extra time that went in implementing their other requests.
What should I do at this point? It's likely that this client will walk away and probably attempt it with another freelancer. I've decided it's not worth it and other they agree to the new X hours and allow me to finish.
It's super complicated now. I totally regret doing jobs on these freelancer websites.