UNAUTHOURISED DEBIT ORDER

I asked Virgin Active to do a debit order on the 7th of every month but to my disappointment they went and debited my account earlier that the agreement date. I even have a confirmation on my phone saying they will debit on the 7th of each month I did not have funds on the day they debited, and my bank has charged me for the debit order attempt when there were insufficient funds. Also, when I went to purchase other personal items, I had insufficient funds in my account because half the money went towards the Virgin active debit order. I am very disappointed and even considering cancelling because I am not sure going forward if this will not happen again.