Abuse from Discovery Heath for premium

I have been emailing *** from the 24th of November 2020 to change my health plan for 2021. No assistance received. I have been on the phone with them today for over 3 hours . No assistance received. All I want is to change my health plan. I call them every day and after a few hours of been cut of or put on hold . I drove to There offices in Nandi Drive this morning only to be told to call the call center. I have been on the web site and was prompted to call the call center. This is not acceptable. I will not pay the higher option as I am requesting to a lower rated plan for 3 months now. Please can anyone assist me .