Sick and tired of being hounded for nothing!

I am so tempted to cancel my account and shop elsewhere. I have been hounded by call centre agents because I owe R10.00 on my account. Yes, R10.00! I got married and was on my honeymoon so ended up paying a week later than normal. I got called for that on my mobile, when I answered, no one spoke. They then called my work phone and again, no one spoke. I called them back and they asked me why my account is in arrears for R10.00 and I explained that when I went into the store to pay, the staff gave me the amount due. This is apparently R10.00 less than what it should've been. NOT MY FAULT! I am sick and tired of being hounded by call centre agents who can't make notes on the system. Why are they not calling the people who owe them more money or don't ever pay their accounts? This is ridiculous. In the space of a week, I have been called 4 times AND I have had to call them back because someone there is not doing their job. They call me and then don't speak so on their end it looks as though they have made the call. Stupid though, because apparently calls are recorded.