OMG.... I FIGURED OUT A FIX!
It is annoying and shouldn't have to do this, EA could just make a cheat code to zero your bill out, but that would be too much work for them.
So I followed all the suggestions, trying different ways to pay and all kinds of junk from removing the mailbox, leaving the lot with my entire family, tried playing another house for awhile... I even deleted the house, nothing worked!
So my family consisted of two Dad's, a toddler, an infant and a baby... One of the things I tried was the splitting your family and moving them... so one Dad took the toddler, the other Dad took the infant and the baby... I moved each one to a different property... then tried moving them back together. Well, I noticed one thing important. The last adult to move out of the house, the positive bill followed them.
Completely annoyed with EA by this point, because if this is a known issue there should be some kind of fix that doesn't require restarting your entire game!!!! Like I said before, could be as simple as them making a cheat code to reset the bills to $0... not asking them to recode and actually even fix the problem!
It was Christmas morning when the Landgrabb's turned off my power... I had three kids, I wanted to do all the Christmas stuff for the kids! BTW, EA, you owe my kids presents, by the time I figured this out it was too late, even with all the pausing I was doing trying to fix it!
FIX:
I noticed the bill followed the last adult to leave the house. Now if you can, save your house, the way you like it (I say if you can, because like all of EA, everything is an uphill battle, it took me about 12 tries to finally get my house/lot to save, kept getting server error try later), go to the gallery, download any ugly Sim you want to, add them to your household. Then move all your original sims using "Split from Household and Move", can even be an empty lot, leaving the ugly Sim you got from the gallery... the go back, move the ugly Sim you don't care about.... the last adult Sim in the house having the glitching bill, the bill will follow them! Go back and get your family, move them back into their house... once again, if you have it decorated the way you want, you can just buy the lot again, bulldoze it and redownload your saved house from your gallery (if you can save it, like I said, EA fights you all the way).
You can then go into manage and delete the ugly Sim you downloaded from the gallery at this point, so you don't have some random playable Sim in your library.
NOTE to EA: This shouldn't be this hard to get rid of a positive $31 bill! This was literally the only fix I could figure out... and if I wouldn't have noticed the bill followed the last adult Sim, I wouldn't have thought to do this... but it is way too many steps to fix your coding error!