Contract not cancelled after I settled it

I paid my settlement amount called back to confirm that they have received my payment. Firstly the person I spoke said I failed the security check after 3 questions which was name & surname, ID number and bank which none of them I answered wrong and when I questioned them about that they told me that they can’t cancel my contract because the option is not there I called again asked to speak to a team leader who called me back did the security check again than the team leader told I have to wait 30 days for my contract to be cancelled after I settled it which does not make any sense but worst of all she **** and said that it’s in my contract that I signed so I asked her for proof that I signed a contract that says that I have to server a 30day notice for a contract I settled.she said she will call me back the same day after 30 minutes she hasn’t called back. Can anyone assist me or do I have to take up the matter with ICASA.