my employer placed a exclusion in the middle of the policy year

and now they willnot even allow me to file a claim. i was able to do all the testing and even see the surgeon and they paid for all of that and when it came time to schedule the surgery they said the exclusion was in place and they will not cover the surgery.i had the appointmnet with the surgeoin 4months before the exclusion was placed and i even had a referrel for teh surgeon before the exclusion was places but it was not filed befause my insurance did not require a referral for me to see a specialist. i live in tn and i work for one of the leading wireless providers and i have spoke to some lawyers and no one will help me. they say to qiut my job so i can get different insurance. i can not get help from anybody. i cant just go apply for a joba nd say by the way does your insurance cover gastric bypass. i need help and i do not know what to do.