Estate Care Center question

My mom closed her account with Wells Fargo in March of this year and passed away in August. I have since received a phone call and a letter asking me to call the estate care center. I called them and the rep didn't really know why they called. The letter arrived today asking me to send a copy of the death certificate (uh, NO). Why are they contacting my mom's estate if her accounts were closed 5 months prior to her passing?