Billing and refunds not received

Good Day,<br> On 28th December 2015 I made an online purchase for groceries and my card was debited for an authorisation. Then on the 30th December 2015 the order was processed but is was less than the authorisation amount as not all the items were available. I then sent a mail to woolworths online to which I received a response that only the amount for the processed order was taken off my account and the balance amount would automatically be returned to me. Now there already is a problem as when I checked my bank statement it reflected that only the authorised. I waited a few days and checked again and it was still the same and no balance was paid back to me for the unavailable items as I was advised. I then sent another mail yesterday stating this fact and guess what, they debited my card for the processed amount yesterday and now my bank statement reflects that 2 amounts given to woolworths. One on 30th December and one on 4th January one for the authorisation amount and one for the processed amount. Why then have I not received my authorised amount back????!!!