Last I checked, I haven't borrowed anything from you. If those 20 people are fine with me paying them back this way, then who the fuck are you? And the 33% they are charging me per month, for late fees, is hardly what I would call measley. 
You're hoping people have written you off and won't check for updates (i.e. won't contact you to get their money back). You have no way to contact them other than BTCJam.
Paying everyone back via BTCJam would include even those who won't check for updates. That would be the right thing to do. This contacting everyone individually is just a bullcrap way to get out of paying what you owe.