Online purchase debiting inconsistencies and product substitution nightmare

made an online purchase with a discount and a voucher, the transaction went through and products were said to be instore. morning of purchase was called by the store before pick up to say that there is no stock of what i had bought, i requested a substitute of EQUAL value and was subsequently assured that that there would be no extra charge and the substitutions where all to the value of my order.KI proceeded to go collect. days later money was deducted from my account from Woolworths, i enquired and was told they would call me back within 24 hours THREE DAYS later i had to call back and was told that the money will be refunded.a called back and was told i would be contacted before end of dy. Next day i had to AGAIN call back only to be told that they will not be refunding the full amount as this was the difference in the order items..... Not sure why they had assured that the store reflected items as available if they were not or why 1)I HAD TO PAY FOR A DIFFERENCE that . i was assured there would not be and 2) Woolworths carried out a transaction on my account without my consent, this seems *******, Also please do not tell me about Ts and Cs because if i speak to your employees and ask them if there is no difference in financial value and they agree, they inturn speak for the Ts and Cs. Definitely a horrible experience for me