This bank changes debit order dates as and when they deem fit - unacceptable

This bank just chops and changes the debit order date as and when they deem fit. They send you a SMS to say they will deduct your instalment on 20 September 2024 "to match your salary date". Who gets paid on the 20th in the first place?!? When I signed my contract, I stipulated the 24th of every month. So you respond to the SMS to say you want to keep your original payment date but they deduct the instalment on the 20th anyway. I got my instalment refunded after some effort and told them to deduct my instalment on the due date (i.e. 24 September 2024). They don't ....instead they update your status on the MFC website as being "in arrears" and send you a letter to make some payment arrangement. How dare they?!? This all affects one's credit score - absolutely disssapointed and dissatisfied with the service. The next car I finance will definately not be through MFC!!!!!!!!