I demand you don't pay me now

So I got my cellphone bill in the mail. They gave me a $100 credit, so I now owe them $-68.42.

I wonder if they'll send me a second bill, demanding the $-68.42 and threatening to turn my account over to a collection agency if they don't pay. The agency will then phone me and, in an extremely hostile and angry voice, demand that they pay me the money right away. Maybe they'll charge themselves interest on my unpaid debt.

Life in Upside Down Land is fun.