Worst service ever

Im so exhausted, i have a loan with them, July 8th i had extra cash and i decided to pay 9000 instead of the 1800 i normally pay monthly. To my shock early August i got messages saying my account is in arrears, i phoned them and explained that i paid 9000 my account is not supposed to be in arrears, i asked to speak to a team leader, we came to an understanding that if i get extra money i will pay the arrears but if i don't then i must just call. Today i phoned after i received an email saying my account was in arrears, i held for 13 minutes only for a call to be dropped, i phoned again and explained my story once again, the lady i spoke to advised that i need to make a payment arrangement, i told her that i cant afford to pay more than my monthly premium she said my account was going to be handed over, i told her that its not fair because i paid 9000 instead of 1800 i pay monthly so why should my account be handed over when i paid 9000 rand. I would understand if i was being handed over because i did not make payment, i made payment of 9000 8th July then didn't pay the month end premium. Its not fair. I still maintain that at the moment i cannot afford to pay extra but if i do get money i will pay extra.