Damelin Accounts Never Up to Date

I was a Student at Damelin Midrand in 2007 and paid my fees in full. In 2009 I get a call from Damelin saying I owe them about R2800. I pay the amount to avoid the admin of trying to prove my case as I has moved to the Free State. 19/08/2015 I get a call from a debt collector claiming I owe Damelin R4800. What ? How? Why is Damelin trying to make money out people? Why aren't your accounts up to date? Damelin owes me, not the other way round!