They Debit Order What ever day they want !!

Bruma Finance are ******. I Signed a contract that a debit order will go off on a certian date. This is ignored. They have my pay slips and bank statements and know my salary date. I am up to date on my payments.<br> I got some money put into my account to buy my gran Oxygen Machine today. BOOM, bruma debit order takes there cut. Now i can't get the Medical Equipment. Its not the Date i signed my debit order form. If anyone reads this who can direct me the right direction to sue them ? Early deductions, inconvience, loss of income and god fobid nothing happens to Gran for not getting on Oxygen or i will include that too.<br> I even took a leave day to sort this out today.