Complain for multiple debit orders.

They debited my account on the 20th and again on the 27th of Jan, no one has monet lying around, the money is for another debit order which will bounce and I have to incur bank charges, when I called I'm told to wait wait for 48hrs which is something that their systems did, o changed my date to the 27th effective Feb but their system went agai in my account despite the fact that they debited me on the 20thi am so frustrated now I need the money urgently.