Breach of contract on debit order arrangement.

I'm very unhappy with finchoice. I like my policy however they keep deducting from my bank account on any day that suits them. I have a debit order on the 3rd of every month, but they went in on the 25th, 30th and even on the 11th. Apparently they debit order mandate allow the debit order 3 days before and 3 days after. Why? I don't understand cause this policy is not in arrears. And a policy is a freedom of choice, unlike a loan. I do not owe finchoice anything and I'm sick and tired of unnecessary bank charges on my bank account. They sent me an email saying if they cancel the debit order they will cancel the policy. I will request a copy of my policy and read it again cause I don't remember anything in the policy stating that.