POOR SERVICE

I am at a lost for words. After following the advice of the agent of how to Change the bank account details on the portal - Vox goes and cancels the debit order but does not change it. So now they tell m the account is in arrears. Thus have been done because i am away, HOW can vox cancel the debit order but not change it. Now they say account is in arrears. Multipl calls and emails but NO ONE WILL REPLY OR GET INTOUCH WITH ME.