Why is GEMS refusing to pay the Dentist?

I am lodging this complaint on behalf of my mother in, Mrs Mpho Mirriam (MM) Vinger, Medical aid number *** on Onyx option. Mrs MM Vinger can be reached at ***. Kindly note that Mrs MM Vinger consulted a dentist, Dr Mabelane Pitso, phone number ***. However, according to Mrs MM Vinger, GEMS is refusing to pay the dentist. What we cannot understand is that Mrs MM Vinger consulted the dentist late last year, and earlier this year, respectively, so the refusal to pay the dentist unacceptable. The urgent assistance by GEMS will be highly appreciated.