IN POCKETING ME

I HAVE POLICY with them my debits order go off on the 27 th of every month .This month they debit me on the 12th I was saving the money to buy some stuff when I get to the store I realise that the money is short when I check my account I notice that they debited my account without informing me. This has really in pocketed me has now I have to wait until I get paid to get what I wanted I have saved for 4 months. I think they need to inform us before they debit.