Rude collections agent and refusing to take my payment arrangement! for my Russels Account

So I am currently on maternity leave and not getting a full salary, I have been waiting for UIF to be paid out so i could not pay my installment for 3 months. I constantly get calls from the legal department and i explain the same thing over and over again. in August i managed to pay a R500 which is all i could afford. I got a call today from the collections once again and the call centre agent was so rude. She said straight she will not accept a R500 payment arrangement because i must pay more. I only go back to work in September that means at the end of September i will only be able to afford the installment again as i am still waiting for my UIF to be paid to me. So when i asked for a statement she said she cant help me. She was so rude to me yet i was trying to come to an agreement with her. I asked for her name because i wanted to lay a complaint with the complaints department, she didn't answer me but rather put the phone down in my ear. I am going to lay a complaint with the NCR as i am willing to pay by they not willing to make the arrangement with me.