Unhappy

I have paid my RCS account in full in December and closed my account, of which I have proof. This month I have received a letter stating my account is in arrears. I phoned RCS, the consultant said she will escellate my enquiry and that RCS will get back to me, this was two weeks ago, still no feedback from RCS. I also send an e-mail a week ago, still no reply. Today I have phoned them and while explaining my issue to the consultant the phone was put down in my ear. This is so unprofessional.