Double deduction

Last month on the 27th my car insurence bounced because there was no sufficient money in the account. This was because the copany I work for experienced technical problems in transfering salaries. When the issue was resolve a day after, I called MIWAY to run a debit order again. To my suprise, they deducted more by R204 and when I called i was told that it was a mistake and that this amount will be credited for next month. This morning again, MIWAY deducted another premium. I do not understand why is this possible. I need that money back