debited 7 months after purchase

I got an SMS from my bank stating that a purchase of R815 at the adidas concept store. I had a look at the transaction and the transaction was done in July 2014. I do not have sufficient funds for the money to go off now. how can the store do this where I had sufficient funds then to process it but they only process it today!<br> frankly I do not even remember doing a purchase on that day it was so long ago. there was a purchase the day before for +- R2000.<br> <br> I need somebody to call and explain this to me , give me proof of the purchase and provide an alternative as I need the funds now.