contesting life insurance beneficiary

Last fall I was asked by a longtime friend to be the beneficiary of her life insurance. She was never married, no children, parents predeceased her. Does have 2 sisters, and twin half brothers. She told me she wrote to me she did not want her sisters to profit from her death. I agreed to be the beneficiary after offering several other suggestions,. She said she would rather me get the money. She went on to say the sisters knew about the life insurance and would probably try to contest it. The beneficiary change was made in October 2015. She passed away unexpectedly the end of Feb 2016. Her one sister told me she died on 02-28-2016. She had publicly asked for prayers, offered by many friends, then refused to respond to any messages, or tell anybody what hospital she was in. Come to find out, down the road, the insured sister had died a week before she told me. She had her cremeated. NO obituary or notice of her death. They live in Texas I live in MO. I contacted her employer and was told YES you are the only beneficiary of the life insurance. They told me to get a death certificate. I complied with all the regulations. THEN was notified that an attorney was contesting the claim for the sisters. I have waited almost 3 months. The workplace told me CIGNA , the life insurance carrier said to issue the claim with me as sole beneficiary. I finally got a letter last week from Cigna saying they received my claim if they needed more info they would conact me. if not they would notify me of their decision. I called them last Thursday and was told it was being contested, they could not tell me who due to privacy. I told them I was aware the sisters would contest, and that I had in writing that she did not want them to receive benefits. BUT there was not reallyl any reason for any of this as I was the sole beneficary appointed by her, within the confines of the insurancepolicy, accepted by them in 2015. He said he had to allow for time for appeals, and would contact me in 21 days. . VERY vague. Then I got a letter dated 05-02-2016 prior to phone conversation saying policy was being contested and I would receive updates every 30 days. THIS IS RIDICULOUS. I do not want to pay an attorney 40% to get it, but there cannot be any disputes . She can and did name anybody she wanted, There was no duress, She was not murdered. It changed months ago. I asked him it this was then to go to court. HE said NO, we make internal decisions. How do I proceed, I believe that they should have paid within 30 days. Do I contact insurance commission. What state the insurance is in PA she lived n Texas I live in MO. she made me beneficiary. I believe I m entitled to the benfits. IF it goes to court, I have done nothing wrong, and would expect them to pay my attorney fees, and sue for such. The insurance then becomes part of the estate if they could possibly win, and she died without health insurance, so big hospital bills, etc. Please help