House insursnce

I have home insurance with outsurance for the past 5years. I even got my cashback. Which is grreat and i appreciate. Now i was paying 888 per month. Which was too much and i lowered my premimiums . I cancel my two debuts because i was low on cas that month. Then i decided to lower my premium to 440. Then they debit the next month after i lower my premium. Second month it bounced and they sent me a message to say they cancelled my insurance. When i call to enguire why they cancel they say my bank wont allow them to debit because the bank has to give me debicheck. I went to the bank and the bank says outsurance should give me debicheck to approve the debit which is true. Outsurance is giving me the ran around. I called and they promise to send the debicheck to this date. Nothing. I am the one loosing here and outsurance has gained a lot . All i want is to have my policy back. 5years is a lot of money