Mango - Zanzibar flight cancellation.

We booked tickets to Zanzibar in December with Mango, however Mango have canceled our return flight on 20/12/2020 and they are not prepared to help us in any way. We have been trying to contact them to find out what is going on but nothing. Nobody can tell us what is going on and the one person we did finally speak to, told us that December is still very far in the future, they will most probably contact us in a week or two. This is the worst experience with any airline company I have ever had.