Double Debit

On the 14 of August 2023 I asked for my debit order dates to be changed due a change in pay date. I received correspondence almost 2 weeks later after I sent another follow up email asking if this has been done.

My normal debit order date was the 26th of each month. Now my debit orders both went off on the 26th as well as the 1st of September leaving me double debited after I got an email correspondence that it has been changed with the amended amounts due to interest.

I was able to reverse the one but not the other due to im assuming its value.