Pathetic service with TAX CERTIFICATE

In 2018 early January i requested my medical aid to be closed and my account was handed over to creditworks then i paid off the last amount of R2508.00. Now in 2019 when i receive my Tax Certificate it has a minus R6102.00. i have been sent to pillar to post about the correction of the Tax certificate.No one is accountable to assist . I spoke to Tenessen the Team leader who told me the account was handed over and no way they can rectify the Tax certificate nor give me a paid up letter. Now this matter seems like i owe Bonitas and make my life a HELL. Not sure if Bonitas is willing to assist me or not my member number is ***. Can you Please tell me who is supposed to assist such a pathetic service.