Personal loan arrangement

2 weeks ago I made an arrangement with nedbank to pay my personal loan as Iam currently struggling financially. Last year I lost my job due to retrenchment but I continued paying regardless of my situation. I couldn't claim retrenchment insurance with them because my loan was less than 3 months old when I got retrenched. We agreed on R3000 instalment to be taken for 3 months and to be reviewed there after. To my surprise nedbank debited me twice this month. The arrangement amount of R3000 and R5300 normal instalment. Now I don't even have money for my rental and food. What was the use of an arrangement if they can not keep their promise. Please help