Refuse to move DebitOrder

I started working at LibertyLife from October 2014 till April 2015, I resigned because there was no income for a period of 5 months. I changed my debit order date to the 15th of each month because thats when I got my salary according to Liberty. But because of no real income my girlfriend transferred money into my Capitec Account to pay my Vehicle. Now I am at a new company since May 2015 which is more stable and where I get a secure income which is being paid the 26th of each month. Now that I can't pay my vehicle on the 15th of each month but rather on the 26th. I want to move my debit order to the 26th of each month. According to WESBANK I am not allowed to move my debit order date and that results in panelty fees that I must pay. I can't accept that because I have the money and will pay my vehicle but Wesbank just refuses to assit me in such a simple matter and likes to make more money out of me!! I will NOT pay the panelties because I am being impaired by this rediculous matter.