easy in, no way out

i have been with this institution for almost two years and was very unhappy with their service. Recently, i have sent numerous emails trying to cancel my policy but have been getting auto response emails that do not help. i have emailed them requesting that they stop the debit order as i cannot stop it from my side. All i have been getting is the same response of "your document is being sent to the relevant department and it will take so many days. first it was 2 working days, than come month end, the debit order went through again, and i am unable to reverse it. i emailed the same document again and now they tell me that it is being sent to the relevant department and this time it's going to take 5 working days. they try to prolong this by all means so that your policy keeps being deducted as they apparently require 30 days to stop it and by the time that your request is processed they will tell you that the deduction has already run.