Bradlows Phoenix Plaza Incompetency

I took a contract with Bradlows for a Bed and a Fridge including insurance for the items. The invoice that is being sent to me every month has alot of extra charges which I was unaware of because I dont even check the statements until today. I'm having an issue with my debit order and their service is pathetic. My debit order date is set for the 1st of every month, however they debit me anytime they feel like. Today they debited me when I didn't even receive my salary for the month as yet and the money they debited was money that my mum's customers put into my account for her because she doesnt have a bank account. Every month they never debit me on my debit Date set and this causes such an inconvenience. What is the purpose of setting up a debit order date if they are going to debit me anytime they feel like. This is utter nonsense and im truly unsatisfied with their pathetic service.