SASFIN Bank fails the seamless online purchase test, dismally

I cannot understand why half the time I cannot make any online card purchases on the App, online purchases via smartphone repeatedly give out an error message, then for some strange reason, following the error message, the bank sends an OTP which I cannot use because the retailer, such as Woolies Dash, has already rejected the purchase, not for insufficient funds, but for an IT error on the part of SASFIN Bank. Some explain this 'error' thing that has plagued my purchase attempts for a week now. What the hell is going on there at SASFIN IT? Thanks for nothing Sasfin Bank. Unhappy client.