MFC poor quality service and attitude from agent

MFC is the most useless vehicle finance house I have ever dealt with! Per contract I stipulated that my account be debited on the 26th of each month. Suddenly 2 months ago they start debiting on the 23rd of which of course the debit order won't go through. I phoned them and they had assured me it has been changed. This month (March) they tried debiting on the 23rd again! And then they have the audacity to send me an email of demand for the payment because my account is in arrears. Then when I phoned them the agent transfers my call after explaining the whole situation to her so that she doesn't have to deal with me!!! Who the hell does she think she is?! I will not be letting go of this. Absolutely shocking service and their personnel needs a hard attitude adjustment.