IS SARS EXEMPTED FROM COMPLIANCE?

On 07.05.2015 I made EFT payment to SARS for an amount presumably due to them, but subsequently established that no amount was due. Since then I have paid at least three in person visits to SARS offices in Kimberley, I contacted them telephonicallky on at least five occasions, written many e-mails and letters to them, but to date no refund has been made. I have various references, amongst them ********** 93 and ********** 06 (Feb 16); ********** 05 (Oct 16) and ********** 84 (Sept 17). One file reference is ********** 395. My e-mails are now met with automatic response indicating that turnaround time is 21 days - the last was on 19 March 2018, 31 days ago. How can you assist?