Breach of Contract

My accounts with Beares clearly states debit orders go off on the 1st of every month. 1 December 2020 the debit orders went of and again last night 15 December 2020 which is in breach of the contract signed. Spoke to the branch manager and she said it is because everyone is getting paid early in December. My Salary gets deposited on the last day of every month regardless what month it is and i don't care about it being December, we work the full month and my salary pay date didn't change for one month.

Please reverse the payments back into my account as i don't simply have money lying around for everyone to debit it when they want to.