Can I sue Aetna for the pain and suffering they've caused me?

My mother recently passed. She was out on LTD ( for lung cancer) when she passed, which started Nov. 3rd. On December 21st she was paid ( by direct deposit )for her month (dec) of LTD. My mother passed on December 24th. I called and notified her employer and Aetna on the 27th of her passing. I specifically asked BOTH for a return call to find out what happens next. Later that evening ( since the time difference on west coast, and where her rep resides) I received a call back from my mothers rep. from Aetna. I again specifically asked what happens now with the ltd benefits and she stated exactly to me that they will send a letter requesting the death certificate and I will receive a letter about an over payment since my mother passed on the 24th and she was paid for the full month, she was over paid from the 25th – 31st (7) days. Ok fine, not a problem, I just have to pay the over payment back… so I was told and thought until the 30th when I see a debit showing on my mothers account for the full amount of the check she was paid on the 21st. I called and asked what the hell was going on, had to wait for west coast rep to call back and she stated that since the payment was still pending ( which is a lie) that it’s their policy to reverse the check, correct the amount and send out a paper check made out to my mothers estate…. this itself is a problem since their isn’t an estate. My mother paid cash for everything, doesn’t own real estate and paid everyone of her bills. Other then that, the money they gave paid her on the 21st processed into her account on the 22nd and we paid her monthly bills with that money. So now I’m using my money to pay her bills since they sneaking took the entire money back. Can I sue them for this and add pain/suffering to it since this has all but killed me from the stress on top of the grief of loosing my mother. Please help!