NSFAS never responds to any contact made to them

I honestly don't understand why NSFAS actually publish it's contact details or even has a twitter account when they are not willing to answer or respond to any of them. I have been trying to call them, email them from different accounts, sent messages on their twitter, but no response. I have paid up my loan, but I still get statements that my account is outstanding, never mind, the calls and smses from their debt collection agencies who never have the latest balances. This is highly frustrating.