I need my money back

I am sooo disappointed with STA travel, I paid for our Easter Zanzibar trip in January before we even knew about Covid. Then when there was lockdown I talked to Kyra Roodt and she said I can't get cash back but a voucher. Now when I email her, the email bounces back and it says the email does not exist. I just need my money, how can they treat us so badly.