Wesbank breaking agreements

We bought a vehicle and financed it through Wesbank. We signed an agreement/debit order for payment on pay day. Wesbank deducts whenever they want. Payment was taken on 20 November for December which was fine because it was as it should be, but today we marked that payment was taken again and not scheduled or according to the said debit order or payment date. Now we have to work out how to survive until pay day which is still 5 days off. Come on Wesbank, this is not even taking off some of the interest but only lining your own pockets. Shame on you for not adhering to the agreement but should we miss a payment or short pay we would immediately received a call and some lovely threats. Not interested in your excuses or your stories. Just very ****ed off with your manner in doing business. Will definitely re-think our finance house when bying our next vehicle.