5hrs and still waiting for a manager to assist

I booked a domestic flight for my father to Joburg tomorrow, 30th of April, Mango decided to urgently change the time of flight and announces through email yesterday. My father is catching an international flight, I addressed the issue on the phone and with emails this morning. It's been 5hrs and I am still waiting for a manager to assist in my matter. <br> <br> The service agent at the refunds department responded in less than 30mins, why should a manager take 5hrs to reply? After 3 calls following up. I do understand they can only refund if it's more than one hour prior to original booked time, but in my case it is not fair to inconvenient their customer like this! If airlines just change time without thinking for their customers, then they will just get bad ratings forever!