Bilateral intravitreal injections

I work for a Retina group, and our Docs do Intravitreal injections. My problem is with United Health Care they are not paying for Bilateral injections, I have coded 67028.RT, and 67028.LT. They denied sates to many frequency of services. Then I coded 67028.50, they denied that as well. Is any one else out there having this problem? If so how are you handling this. Thanks You!!