Very bad service

I took out Bonitas medical aid in January 2020. Before hand I did research and I requested a list of doctors covered on the Bon cap plan. I received the list in Nov 2019 and I saw that Medicross Benoni is on the list. I was happy and joined the medical aid. I had my 3 months waiting period. I went to the doctor twice in the last month or 2. All of the sudden I receive an account from the doctor telling me that the medical aid is not paying for the consultation. I contacted Bonitas and they advised me that medicross Benoni left the Bon cap plan in 2017 (yes, 2017, we are in 2020 now) and that they will not pay the consultation. So they send me a list that is 3 years old! And they tell me that it is the doctor's responsibility to let Bonitas know when they leave the medical plan. This is not acceptable and not my responsibility and i will not pay for that consultation. This is between medicross and Bonitas. I am communicating with Bonitas via email and in all my mails (al 20 of them) I request that someone phone me to discuss this matter. I haven't receive any call up to today. I moved from Momentum to Bonitas because according to everyone Bonitas is the Best. I don't believe this anymore. I don't get any assistance from them or good service.