Account debited in error

I requested Liberty to reduce my monthly contribution towards my retirement annuity in December 2017. I filled in the necessary forms and received confirmation that my request had been actioned. On the debit order date, Liberty debited the old amount and the new contribution amounts. I then reversed one amount resulting in them being unable to debit my account in Jan due to a block from the bank. I then called them on 29 Jan and told them I will make a manual payment, but they should update my banking details to debit my new account on 20 Feb. For some reason they decided to debit my account on 30 Jan and now I need to fill in forms or go back to the bank to reverse the debit. I don't have the time to be running around for errors on Liberty's side.

Please correct asap or cancel my policy.