Accounts and Call Centre

Hi,<br> <br> I have never experienced such bad handling of a customer complaint in my life. I have complained about my account and finally I get an email to say we have tried to call you many times and no answer when I have not received one missed call on my phone from them. Finally I called the call centre three times and after 20 minutes of holding on, they just put the phone down and never call me back.<br> <br> I have emailed customer service