Double Payment Error

I made a purchase from Zando on the 13th of May 2020 to the value of R2319. Order *** (double payment) & *** (items received). A system error occured and the amount was deducted from my account twice. I immediately informed Zando of the error. A customer service agent, Aviwe, responded by apologising for the error made. To date, I have not received my refund. I have e-mailed them numerous times with a copy of my bank statement reflecting the double payment & I have tried to phone them but their number is not in use at the moment due to COVID-19. I am so dissappointed in Zando. I have been a loyal fashionista supporting them for years but now I am not sure if I'll ever order from them again. The service has become so bad with no communication or support offered... & they take ages to deliver.