Non-closure of account

I gave notice on 1st April 2015 for my Telkom account to be closed on 1st May 2015 as I sold my property and moved overseas. I called Telkom before my departure and received confirmation of the closure of my account being scheduled for 1st May 2015 as per my request. I also received a cancellation ***. Due to the billing period of my account I was invoiced for half the month of May 2015 in advance and was assured to be credited on the final bill. However, this has not happened, instead I received another account billing for the month of June 2015. I tried to raise a dispute online but after numerous attempts kept receiving error messages. Another option online was to 'escalate a complaint' or send an email to [Email Removed] both of which I did on 18th May 2015 requesting the matter to be retictified. Up until now I have not received any response from Telkom and my account still shows the same outstanding balance. I live overseas now and I am not prepared to waste time and money on overseas phone calls because of Telkom's incompetence.