Terrible service or help

I purchased data on my mtn app and payfast was the third party payment app. After my data purchase someone hacked payfast with my credentials and ordered take aways through Mr D in Cape Town ( not even close to where i am based). There were 4 transactions that added up to just under R700. I sent numerous emails trying to sort this seeing that my bank Capitec couldn’t help me because of the authentication that i apparently gave. But no word from anyone to help me. I thought that all the apps would be quite secure especially when its linked to you bank account and maybe that they could pause the payments when they see its not in your history to order Mr D and especially in a far away place….