cigna dental cigna giving false information before sign up! Philadelphia Pennsylvania

Before my sign up date with Cigna Dental on 07/01/2016, Cigna Dental customer service informed me by phone there would be no benefit difference between in and out of network orthodontists ($1,500 lifetime benefit) and they didn't mention anything about the maximum allowable charge for out of network providers only. I knew I was given false info months after signing the contractual agreement with my orthodontist on 07/20/2016 and paying the $600 out-of-pocket deposit. Cigna processed the pre-approval document (outlining the benefits they will pay and how much I owe) on 9/21/2016. That's 2 months after me signing the orthodontist agreement!

Under the signed agreement I'm responsible for all charges regardless of what my insurance provider pays. So that leaves me with $623 of unexpected out-of-pocket fees (I cannot afford). Cigna said they will only cover $877 of the $1,500 lifetime benefit (aka maximum allowable charge). Cigna said they can't review the calls prior 07/01/2016 as I wasn't a customer yet. I will not pay for their mistake (giving false/omitted information). I filed an appeal with Cigna Dental Appeals but they refuse to accurately respond to my request due the fact I was given false information. I have receipts of my deposit and signed agreement but Cigna refuses to receive the evidence! They are not BBB accredited and have very bad reviews so I'm not sure how this unethical company still operates!