VERY BAD SERVICE!!!!!!!!

I currently am on the Blue Door Plus plan. I needed to go to the dentist in March so i called the call centre to confirm which dentist is covered under my network. I received an email stating that the Medicross Boksburg is covered, so i decided to go there. A month later i get a call from Medicross Boksburg saying that i have to pay for the visit as the medical aid did not pay for it. This is honestly *******. Why should i pay if i received an email saying that the dentist is covered!!!