Poor Service from Telkom when trying to cancel a service

Have been trying to contact the call centre to cancel a fixed line and keep getting told they are offline or they never answer. Went Into the local telkom store and was told I can only log the request via the call centre. Furthermore they loaded some extra service charge on the wifi contract we have for a service we never requested. What is the next step to get ahold of Telkom if they are offline and always take forever to answer the call centre number?