The only time we have seen the settled balance been reassigned or sold to another collection agency is when the collection agency or creditor misapplies the settlement as a partial payment only.
It's usually just an honest mistake on the part of their accounting department.
That’s the main reason why its important to make sure the settlement is binding on both parties so if something like this does happen, it can easily be corrected.
I can't count the number of times people have tried to settle on their own and been burned because their paperwork isn't in order and another collection agency bangs on their door looking for more money. Sometimes this has happened a few months later, other times it can happen a couple of years down the road.
Total Debt Freedom ensures this sort of thing is not an issue for our clients; if you are settling your own debt, be sure you know what you are doing to avoid this potential problem.