Doubled my Debit order amount without any permission

I changed banks and therefore had to change my Discovery Debit order (only took 3 months). I paid EFT for the three months but when the first debit order went through, I noticed they had debited 2 months' worth. No communication nothing!

I made contact (Via Whatsapp, frustrating!) and they say I must come back to them in a weeks time as that's how long it takes for MY money to reflect on their side. I run a tight budget and I need to borrow money in order to wait for the refund.