Ridiculous international roaming tarrifs

Very ridiculous international roaming tarrifs. I requested the operator to activate roaming for calls while I was travelling to Dubai, I'm on prepaid so I loaded R1k airtime which I believed was more than enough for the 5 days I was traveling. To my surprise when I got back no amount was deducted from my airtime. End of the month I got a bill from MTN for R5k charge gvg