Avis ignoring double payment refund request

Avis Tax Invoice E***.<br> African Bank Visa payment on 2015-01-11 (R2699).<br> Zandalee Goosen from Avis claimed that payment was reversed and demanded payment again.<br> I made another payment (R2699) on 2015-05-29 after threatening letters to my parents.<br> Neither Zandalee Goosen nor Selome van Niekerk (from Nedbank) wanted to assist us further and referred us to African Bank.<br> African Bank investigated and confirmed that initial payment was successful and never reversed according to Visa, along with proof which I have e-mailed to both Zandalee & Selome on 2015-08-12. Neither bothered to reply to my e-mail.