Couldn't find my payment / Don't answer emails

I booked my parents a trip to Cape Town and paid for their trip via Checkers, as my credit card would not be there. Lo and behold, they could not find the record of the payment, despite me having receipts. Now my parents are due to travel back and Mango has not responded to my email with copies of the receipts from a number of days ago, and I can't get through on the phone and have been waiting in their call centre queue for more than an hour. Never had such bad service! I am a platinum client of their parent company SAA, and there was little they could do to remedy the situation.