Insurance Issues, has this happened to anyone?

okay here's my problem. In February when i started this process, i emailed my HR dept who then email our insurance rep from CIGNA, and asked if they cover the lapband or gastric bypass. I received an email back from our insurance company CIGNA saying yes if its medically necessary - i have an email from them themselves. Now the doctor called me tonight and canceled my date of Dec. 6th because the insurance company said they don't  is.) I called the HR dept at my company and told them what happened and there going to look into it, because HR said it was too. When i talked to CIGNA they said someone must of messed up and didn't include it so (CIGNA said) someone needs to call them up and fix it to say that they do. Do i have any legal rights here? I have just paid thousands of dollars for the year going through everything in doctors bills and i just can't believe this is happening.Has this happened to anyone? Does anyone have any suggestions? Does anyone think i have any legal rights? Who do i fight with? I don't want to **** anyone off but i've been working hard on this. Please any suggestions would be great. thanks