After paying of my loan a debit order went through for almost a R1000, where I proceeded to call and make corrections as I have paid off the outstanding amount

After paying of my loan a debit order went through for almost a R1000, where I proceeded to call and make corrections as I have paid off the outstanding amount. After multiple calls the money was return to me BUT the amount was half of what was owed to me. This is a greate inconvenience because I did explain the amount owed on previous calls and the urgent need of it.