Momentum has gone back on their word and contradicted our agreement

I had a very long battle with the medical aid as I needed an urgent surgery for my endometriosis as my colon was severely affected, and after Momentum agreed that they cannot offer me a doctor on the associated list to perform my surgery, they agreed to pay the full rates/shortfalls of my specialists.

However, Momentum has contradicted our agreement and has paid a small amount towards each specialist, and now I have a shortfall of R26 933.79

PLEASE investigate this further, as this is a huge contradiction and I have fought very hard for this case. I cannot agree with the amount that has been paid to me, it is unfair and untruthful. I have the screenshots of our correspondence where they have agreed to pay my shortfalls.

I don't know what to do now.