RAIN OWING THEIR CUSTOMERS MONEY

We have the Rain wifi at our house, that my son pay for, so Rain took the money from his account every month around the 25th - R499.00. The 25th August they did not take the money. Then he received a mail from them that the wifi has not been paid. There was more then enough money in his account, so he phoned them, they said that all Capitec customers Debit order were changed to 0.00 (we dont know why), but he EFT the money into their account, a day or so later they Debit order his account again with the same amount. Now he battles to get the money out of them. He phone them HOW MANY TIME. Since he have phone them nobody did not escalated this to the accounts department to process this refund. Why does this happen? Why does they not pay the money back????? I cannot believe that we can get this kind of service in South Africa, but they want the business. Please could somebody help to get this money back from Rain - PLEASE PLEASE!!!!!!