Cancelled flight and delayed refund

I booked a flight travelling from East London to Johannesburg for the 4th May and the airline notified us that the flight was cancelled and whether we would like a full refund. Firstly they cancelled about 2 days before the scheduled flight and we had to make an alternative plan which we hadn’t budgeted for. Secondly how do you cancel a flight 2 days before, what if we won’t able to make another plan. This airline is both unprofessional and inconsiderate and to top it off, apparently refunds are paid 6 to 12 weeks time. This almost feels like they make the refund process so long so that we forget we due for a refund. I will never make a booking with them ever again and would suggest others do the same.