You will need to send a copy of the death certificate and a selfie of you by the open casket to your pension office so they can update their records. It may take a month or two before you start receiving the revised payment.
Sorry to hear. I can only offer you my experience with a different employer as I have not left UPS yet. The first person I would call is the plan administrator to discuss the steps involved. If the results in a dead end, I would then call UPS finance department to see if they can point you in the right direction.
Occasionally, the original administrator is not the current one as the plans sometimes get sold to other administrators.
No, I do not get that money now that she has died the pension is only guaranteed for 120 months ( 10 years) even though I get my portion what she was getting I lose. That pretty much sucks