CELL C - TERRIBLE AFTER SALES SERVICE

i have had a query with Cell C on my account for the last three months that has still not been sorted. I am being charged for a sim card that came as part of the package contract on upgrade that was not requested but had to be taken as it was part of the package. I have asked them to give me a call back after 5pm in the evenings as the account holder will only be available then and to date all i receive is SMS stating that they cant get hold of me, or they call the account holder during working hours and he is not available. ref number is ***. the service from Cell C is atrocious. we have been clients with them for 20 years and I am very disappointed in the after sales service that I have received this time. not even the store can assist me.