Okoa jahazi? 5bob!! You borrow 50, use it, next time you top up with 100 your balance will be 45

What @vvs is saying is that when Safaricom gives you 500/= airtime loan it's not like they get Kshs. 500/= from "their pocket". If you don't pay, they actually don't lose what they had in the first place.

Of course Safcom will still do everything to ensure you pay but default doesn't have the same effects as for banks and shylocks who actually part with hard cash.

As for the Kenya Power one, I suspect they have some arrangement where by if you don't pay, any time you try to buy tokens using other means, your money is "swallowed" to pay the debt. And in case you qualify for certain amounts depending on your profile.

Sellers stepping in.

Nzioka Waita joined Safaricom in 2001 as a Legal Officer responsible for Site Acquisition and thereafter rose steadily through the ranks to serve the company in various capacities ranging from his role as Legal Services Manager between 2002 and 2007 and thereafter as Head of Legal & Regulatory Affairs between the years of 2007and 2010 followed by a brief stint as Head of Strategy & New Business responsible for driving the company's mergers and acquisitions agenda, a position he held until April 2011 when he took up his present role as Corporate Affairs Director.
Nzioka is an Advocate of the High Court of Kenya and a Certified Public Secretary, he holds a Bachelor of Laws (LLB) degree from the University of Sheffield and a Post Graduate Diploma in IT & Communications Law from Queen Mary, University of London both in the United Kingdom.
Nzioka is also a founding Trustee of the Safaricom Foundation, a role he has held from August 2003.