Unfair dismissal during lockdown time

After working only 1 month there all of sudden my shifts become less and for the last two weeks I only got 4 days to work for R20 an hour. While the rest of the cashiers worked more than 3shifts per week. I got an message asking if I can come in today at 8-1. Just to be informed the manager is firing me because business is slow. While I know thats not the case.