Received a call as if my account are overdue

Just received a phone call, I was treated as if Im overdue on my account. Also the lady who phoned me said the payment I must make the end of this month is over R400, while I know my installment is only R330 and I overpaid currently I only have to pay Under R60. She even asked when I will make the payment, I never ever missed a payment and I do monthly a eft way before the fist of each month. I did not appreciate this call. And this lady did not had the totals even correct.