Nedbank pathetic service

10 years ago my son had a loan with nedbank. He lost his job and couldn't pay. He managed to get a job last year. In January this year he made an arrangement to pay nedbank R1k a month towards his loan. My son lost his job again in April this year. Nedbank deducted R13k from his account without his consent. I made several calls to nedbank but they refused to refund the money. Please check your statements. On the 3rd June I purchased a nedbank avo voucher for R2500 and my son purchased a voucher for R1000. We have not received the voucher payment. I phoned Avo money and they assured me that we will receive the money within 3 to 7 working days. I received an email with a reference number. After 3 days I contacted avo money. They advised me to contact nedbank. Since then I cannot get hold of a nedbank consultant. I've been holding on for an hour to 2 hours each day on an automated voice call. You hang on endlessly. Nobody answers. I tried calling various departments. They transfer me back to avo department and again I just hold on in vain. I really really do not know what to do anymore. How do I get my money back from Avo nedbank. The service and technology is pathetic