Still no resolvement after 6months - being double charged for 2 lines despite cancelling!

Since August 2018 when querying why I was double charged at my new address AND for my new address (despite cancelling previous contract) it has been unresolved.

Several hours on call centers and monthly followups did not resolve the issue. Up to now I have not been credited for the months where only one line was active.

Pls urgently resolve otherwise I will have to go to media. 6months is more than enough to resolve a matter like this!

Callcenter manager explained there was a backlog of up to 3 months but its now been 6months!!