Call centre agents stalking and arrogance but no statements received.

I am very frustrated with Nedbank. They phone me every day at least 3times regarding an old personal loan. I have told them on numerous occasions that I cannot speak to them during working hours as I am getting paid per hour. They just completely ignore my wishes and have no respect for my wishes. The lady who phoned me today was so arrogant by telling me how can I say I am not available as I am speaking to her and why do I not pay my account. This is ridiculous as I have been paying every month but the interest at this stage exceeds the capital balance and is capped as per the Common Law. I can however not exactly calculate this as I have not received any statements from Desember 2016. I cannot understand how I am supposed to pay for an account for which I do not receive any statements. This is unacceptable for a big bank like Nedbank who is supposed to adhere to Laws and regulations.