Account Double Charge and NO HELP to solve it

<p>I upgraded my Phone from iPhone 6 to 7 in the month it came up and all went well. Been a happy customer since 1994 (mostly). My February account had my LINE rental on for February but then my NEXT INVOICE IN MARCH again had LINE RENTAL and DATA on for February AND then for MARCH. I have been double invoiced for February on two different INVOICES - having spent an hour on the phone 10 days ago it finally was agreed with the 3rd person spoken to that it was indeed an error. He was going to send me a corrected statement and resolve it. (I have two reference numbers for call logged) HOWEVER the next invoice arrived and STATEMENT and SHOWS my SHORT PAYMENT as still outstanding - when I went to the local VODACOM shop they have others with same issue and tried to assist by calling VODACOM - the phone was put down in the ladies ear. I have tried calling today and told lines over full and log onto website or "basically " DONT CALL US WE MIGHT CALL YOU. How do I get to speak to someone who will resolve this clearly made easy to see MISTAKE ? </p>