As much as this looks good, sorry you hear you got screwed over for doing a commission for free unvoluntarily. My suggestion is that the next person who commissions you, keep tabs on them from time to time, maybe every 3 days or a week, to see if you can still connect with them. If you can't and haven't finished the commission yet, put it on hold until they contact you back, otherwise put it in the "scrapped vault".