Dissatisfied with call centre and app services.

Discovery Health call centre sucks!!! I am battling with a simple thing like a tax certificate, the app is useless therefore I tried the call centre not that they are any better than the app. The app continuously gives me an error message "could not retrieve information please try again later". The Teamleader from the call centre called me and promised that she had sent me my tax certificate via email I am still waiting for it. What do we do as customers when neither the app or agents can be of assistance to you? I am very dissatisfied with the overall service I have received from calling them twice to countless app requests for a simple tax certificate.