Unprocessed transaction

made an online purchase from ZARA and money was deducted from my account with a pre authorisation status on the 20 June on the 23 June a duplicate amount was deducted from my account by ZARA, the deduction that was taken on the 20th was not processed when I check my bank statement.Zara says it is the banks problem to fix because they’re are the ones who deducted twice with the other transaction unprocessed.