debited for something i bought 4 months ago

Good day<br> <br> I bought a fridge at ok furniture in gugulethu on the 28th Feb 2015 for R3849 and I used my cheq card to swipe and I received an sms confirming that the amount was reserved for the purchase and that money was not available in my available balance, to my surprise when I check my statement today I see that I am charged again and I have never authorised for that amount to be deducted again. I am really disappointed in FNB for allowing this to happen to my account without my consent. Why am I being charged twice. I want that money to be refunded into my account asap.<br>