Impossible to close Tymebank account

I was quite chuffed with tymebank's offering for good interest but now on trying to close the account they told me I could not close the account because I had R0.13 in the account. However my online banking showed -R6.87 balance due to a R7 inactivity charge. I then transferred R6.87 to the account to zero it but then it charged me R0.30 for the sms notification so I had -R0.30 in the account, but the agent said I had R6.70 in the account and should buy airtime but I could not because the account reflected the negative amount. I have since had to spend more than R100 on calling customer services to close the account because of the R0.13 balance that they could not write off.