Airline cancelled our ticket without our knowledge

We have been put through the ringer by this airline. Firstly our flight was cancelled flying from Johannesburg to Mumbai and while they did put us on a different flight we were 5 hours late and missed our connecting flight, which we had to repurchase. Thinking the worst was over, on our way back we find out that they have cancelled our return ticket after cancelling our outbound flight. We spent 14 hours in transit, where we were treated horribly with no water. We ultimately had to buy a new ticket to get back to South Africa, which ridiculously enough we couldn't even purchase at the counters in transit. My sister had to buy it out of South Africa on the internet at 3:00 in the morning. We have been told that we would be reimbursed and that the airlines are working on it, but we have received no updates and it's been over a week.