United HealthCare Services

I have been trying to get a billing situation resolved for months with Tekwani Vision Center in St. Charles Missouri. I have called so many times with no results mainly because the customer service department will say they will investigate and call me back and they dont. I have been fighting since August. Tekwani Vision is asking me to pay a second deductible and I only have to pay one which. My complaint is that I need the support of UHC to get this resovle because the vision center is now threatening me with ruining my credit.
I want a rep from UHC to return my calls like they promised