Violation of Payment arrangement - Refund wanted!

I would like to request Cartrack to kindly refund the money they debited on my account on the 15th of December 2021. I had an agreement in place with cartrack to make payments of R300 monthly, not R2000 which was the amount which was taken from my account. Payment arrangements are put in Place for a reason - it’s another thing when these arrangements are violated. Especially cause the debit order mandate that i agreed to was for R300 not R2000! I’m so tired of cartrack. Please can you urgently issue a refund of my money.