***** in mtn extratime service

Im very disappointed with mtn SA I bought R30 airtime using extratime service and I recieve a sms that says your recharge was successful but never received my airtime. It not the first time it happens last month I called customer care and I also sent the email to their ***** department but never got help now it the second time that Im going to pay for airtime that I never received with interest for the second time I'm not happy at all my no is ***