Horrible service

I have a vehicle insurance with myway. I thought i am with the best and smart insurer until today.

I have an agreement with myway to debit me on the 20th of every month,to my surprise they attempted to debit before the date we agreed on without even informing me. They attempt was not a success now they are sending me sms's that threaten my cover with them. Who's fault was it that myway went onto my account without success on a date that was not agreed? Now i am being asked to make an arrangement,what arrangement because i had made an arrangement for the 20th when i first took the policy? Myway should have at least communicated with me that they wish to attempt an early debit so that i can advise whether they should go ahead or stick to our original arrangement