Billing team ignores emails from call centre agents!!!

I have been calling ADT since the beginning of the year requesting them to change the date of my debit order since I changed jobs and no longer get paid on the same date. I have literally called over five times and still to date it hasn't been changed. I was first told to send an email to some address stating I wanted it changed but nothing. The only thing I get from the call centre are agents telling me they can't change the date but can only forward my request to someone. But I don't know whether whoever they forward to gets the emails and just ignore them!!!! Literally since beginning of the year and nothing happens!!! This is affecting my credit record as the debit order bounces but no one seems to care at ADT!!! Why have debit order date options for customers if you are going to ignore their requests they need dates to be changed???!!