Taking forever to do refund

I booked my flights between Johannesburg and Durban (27 December 2017 and 2 January 2018) through Flight Centre. Unfortunately I landed in hospital and could not make the flight. I contacted Flight Centre in this regard and they asked for proof that I was in hospital in order to refund me. I sent this through. However, now, almost two months later, they still have not refunded me. I contacted Lorraine in this regard. Initially she said the refund would take a month, but now she says it can take up tp three months. I just feel that this is unacceptable. Even if they are dealing with different airlines, they still need to provide service promptly.