Unauthorised debit order

I had made a purchase from Joshua Doore at the Phoenix Plaza in September 2015. I purchased two grafton everest magnum lounge suites. 1 was paid for in the cash and the other was taken on my name however my mum would make cash payments at the end of each month. The consultant was completely aware of this so was the person handling the paperwork. We were told the 1st payment would be on 1 november 2015. My mum went and paid more than the required some on the 1st. However today a debit order went out of my account to my surprise. I am a govt employee we were paid today. I got a bank statement and went to the store for a refund as those funds deducted are meant for my other debit orders. I received such hostilty for asking for a refund. Apparently my debit was not reflecting on their system. I was so peeved as I had not authorised for a debit order facility to be enabled on my acc from this store. No one made any attempt to assist me. I was highly irrate more so when the manager was so rude and sarcastic towards me. When i had made.my purchases in september i was treated with such dignity and respect however their after care service stinks. I was told to wait for my money until monday