I have UHC Choice Plus PS1

I have a written exclusion in the policy.  I was told by UHC that my employer desides what is covered and what isn't covered but....................... my employer says no that they have tried to add WLS to there coverage but UHC will not let them.  So who is telling the truth and who isn't?  I just don't understand how Ins. Co. work!  If I have to pay for my premiums ( spelling? ) why can't i have a say in whats covered and whats not?  I see all these other people on here who have UHC choice plus getting approved it sucks to be part of the few that is not! Billie Jean