Poor Service

I booked a flight last month from CPT to JHB. Last week Sunday I got bad news that my cousin was burnt in the house while he was sleeping. Unfortunately he passed away so had to cancel my trip to JHB. Due to the funeral that will be happening this weekend, I spoke to a guy from mango regarding my refund and cancelling the trip. They promised to do so if can send them proof(death certificate) I did as requested. its been 5 days and they never came back to me. I called them on Friday and spoke to a lady called Lulu as she confirmed that they will send me my voucher. They never did.