DEBIT ORDER NIGHTMARE

I just took car insurance with MiWay and I was quite happy wit the premium, the agreement on the policy is that they must debit on the 15th of every month. On 14th October I received an sms from Miway saying my debit order for 15 October has bounced and I must remember no premium no cover. I was quite surprised because this was not the agreement on the policy schedule, now my bank is charging me for the bounced debit order and when I call Miway to enquire about this they tell me about a policy I took in the past with them but I asked them why was the first debit on the accurate and correct date and why did they not mention the past policy when we finalizing the policy. Now my question to Miway is why we even have policy schedules if we are not going to adhere to what is said on the documents? Can you guys just decide to change the debit order date? I am guessing that even the bank charges against me are not your concern right? Why do we have policy schedules if you do not honour what is written? So since you guys debited on the wrong date it means I am not covered right at the moment , right? Bounced debit orders reflect badly on my profile and I am working so hard to get it under control