Double charging

Reported duplicate charging on my bill. I have 3 cell numbers linked in ONE bill, one of them after being extended in May was being charged double since June, I reported 9th July the problem, today the 21st I had to phone back, NO FEEDBACK from Autopage, just to be told the accounts told them they looked at the number & nothing wrong, but they looked just at the MAIN number & not at the 2 linked numbers. When I told this lady today she said everything was correct captured so she will submit AGAIN I have to wait 7 working days. 2 issues WHY did Lennard not come back to me as the lady today said he should have & WHY did the lady in accounts NOT do her job properly, leading me to have to pay double amounts every month AS WELL as having to GO BACK and restart the whole inquiry AGAIN!!!!!!