Mango won't refund money taken erroneously

I made a booking for 2 people from Port Elizabeth to Johannesburg in March 2015. The amount was deducted off my business account instead of my personal account. There was a problem with the booking and I did not realise that the amount had gone through and made other plans. I have been trying to get a refund since March and there is always an excuse that they need some or other document to give me my money back. Even after giving them what they want I am still waiting for the refund. I have been waiting on the phone for 20 minutes and no-one answers the phone and they do not reply to my emails. Pathetic Service.