I want my money back

Hellopeter i made an online purchase from pick n pay on black friday for 50inch Aim TV and the payment was processed on the 1st of December for me to collect the TV on the 2nd of December at pick n pay family store in edenvale, when i got there the supervisor told me that the TV is not in stock and the the following day I contacted pick n pay online to let them know and there was no answer as to why they processed the payment while they did not check with the store if they store has enough stock, so last week i got an email that my order was cancelled due to non payment while they debited the payment so now when i ask for refund they told me that i have to go to my bank to clear the funds back into my account, of which i did and the bank told me that they cant do that to a payment that was processed online so pick n pay must reverse the payment for me. Right now the insist that they did not authorize the payment but they reserved it so it must be cleared by my bank so can you please help me get my refund back i have the bank statement with me