Unforgettable. Natalie Cole was featured in the Grammy Awards‘ In Memoriam segment on Monday, February 15, but her family is unhappy that the beloved singer, who died at age 65 in December, was not given a more fitting, substantial tribute.

While Glenn Frey, Motorhead singer Lemmy Kilmister, B.B. King, Earth, Wind & Fire’s Maurice White and David Bowie were all remembered in separate musical segments, the “Unforgettable” singer, who won nine Grammy Awards, was not.

“Sadly a FORGETTABLE tribute to Natalie Cole,” the singer’s sisters, twins Timolin and Casey Cole, told Entertainment Tonight the day after the show. “Words cannot express the outrage and utter disappointment at the disrespectful tribute, or lack thereof, to a legendary artist such as our sister.”

Pointing out that the daughter of singer Nat King Cole was nominated for 21 Grammys over a career that spanned five decades, the siblings added, “It was shameless the way they minimized her legacy. We will find solace in her legacy as well as her endless fans around the world.”

Timolin and Casey were not the only ones who expressed their disappointment over the snub; actress Holly Robinson Peete referenced Black History Month when she tweeted on Monday night: “We lost so many greats but Natalie Cole 1st African American to win Best New Artist deserved a tribute #Grammys #BHM.”

We lost so many greats but Natalie Cole 1st African American to win Best New Artist deserved a tribute #Grammys #BHM pic.twitter.com/tKMbrUtBkL — Holly Robinson Peete (@hollyrpeete) February 16, 2016

Cole, who rose to fame in the ’70s with hits including “This Will Be (An Everlasting Love)”; battled drug and alcohol addiction before making a comeback in the late ’80s — culminating in her celebrated Unforgettable… With Love album, a tribute to her late father — died on December 31 at the age of 65 after battling health issues for several years.