The credit card statement *******

Despite numerous calls and emails to Standard Bank Card division, I cannot get a large amount refunded. A credit card in June 2013 shows a balance of R-9546.73 and then the closing balance jumps to R-36547.53. Why does Standard bank call a client endlessly for payments but does not return on call or email regarding a inaccurate balance? Is this company policy? Ignore clients until they go away?