My husband had basic life Insurance

My husband retired from A T & T. He worked 23 years. He passed away in April. I was told that I am his beneficiary by the survival benefit team, I already knew that because I was at the computer with my husband when he made me his beneficiary and he also gave me dual power of attorney. After several months went by I called At&t, they told me they had completed their side, so they transferred me to Met life.  Met life stated that I am not the beneficiary, I do not understand because when my husband made me the beneficiary we called AT & T and they told us we can go on the website and make me the beneficiary .

Can someone please give me some assistance. Met life took my telephone number but did not give me a address to write this letter.