Lack of service and *********** Organization

We have settled our account with Telkom, when requesting a paid up letter, we find out after 2months they owe us a Credit (which they have not yet paid) and everytime we call, they say nobody has requested the paid up letter! It's 2weeks of struggling with this unacceptable behavior and lack of service delivery from Telkom! Do not have any accounts with this *********** Organization