Changed Debit or date without my concent

Good day; Policy no: ********** 65 I have a Life Policy with 1Life for the past 10years. The debit order for this policy goes off on the 25th of every month and that is how it has been since inception.

In August 2017 I change banks and informed them of the change. On the 25th July 2017 they debit my old bank account and the new debit order would be for the 25th August 2017. On the 08th August 1Life went and debited my New Bank Account without my consent or knowledge with the result my account went into a negative because there was no money in my bank.

I received confirmation from my New Bank informing me that one of my debit orders did not go through because there were no funds.

I contacted 1Life to find out why did they debit my account on 08th because I did not give them permission. The debit order was then change to the 25th and in August they debited my account. On the 15th September they debited my Bank Account again and then I received a letter informing that my debit date has changed to the 15th of each month (considering that I get paid on the 25th).

Again I contacted 1Life this time threating them, because I did not change my debit order date in writing or verbally with them.

On all the attachments it shows that the debit order date of the 25th after sending my new bank details. The fist attachment is them informing of the change of my debit date, I DID NOT GIVE THEM PERMISSION TO CHANGE THE DATE. THIS IS MY CONCERN WITH 1LIFE WHICH I NEED THEM TO EXPLAIN TO ME WHY WAS IT CHNAGED.