Incorrect debit order

I am moving overseas this month and therefore cancelled my vodacom contact (switched to prepaid) last month. I phoned vodacom about five times to check that they captured it correctly on the system. Each time they told me that it was cancelled with the last debit order to go off on the 1st of June and that I would get an sms and emailed confirmation. I never received either. Come the 1st, my account was not credited with the normal amount. A bit annoying but no problem, I just bought a R50 airtime voucher yesterday, incase there was a delay in crediting the amount. This morning my usual vodacom debit order goes off as planned but still no money reflecting for me to use. And even if it did, I don’t want or need it anymore as I am leaving in 2 week’s time. Please can someone assist me in reversing the debit order and assurance that this won’t happen in the months to come?!