For 51-year-old Faron Butler, the thing he cherished most after his daughter's death was being able to hear her voice.
"Every time I had a bad day or just wanted to listen to her I'd go through my old voicemails," Butler told ABCNews.com through tears. "I had one that I'd play over and over again. She'd be saying 'Daddy, I love you and I miss you.'"
He said he was shocked when a few weeks ago he went to hear that familiar voice, only to find out the voicemail had been erased.
"I was going through my messages after a friend called me and was stunned when it said 'no saved messages.' I mean, my heart just stopped. It tears me up," Butler said.
Butler's daughter Rhema was 12 years old when she was diagnosed with desmoplastic cancer. She died two years later, on June 6, 2011.
Butler, who lives in Elma, Washington and has two other children, says he was offered a free trial of T-Mobile's "voice-to-text" service when Rehema's messages were deleted without warning. He says he called the company, asking them to recover the voicemails.
T-Mobile told Butler there was no way to get them back.
"They should have warned me, or I would have never ever done it," Butler said. "Just complete negligence on their part."
For Rhema's sister Kirsey, the voicemails meant being able to hold onto the friendship she and her sister shared.
"When someone dies you hold onto memories, pictures and cards," Kirsey said. "Now with technology you can hear the voicemails, and I'd go home and listen to her voice all the time. Now I can't, and it's awful."
T-Mobile released a statement to ABC affiliate KOMO in Seattle, saying, "T-Mobile deeply regrets the sorrow the Butler family is experiencing.
"When saving voice mail messages long-term, customers receive an alert and are prompted to re-save messages that they'd like to keep. Unfortunately, when the voicemail-to-text feature was added, which has a shorter window for saving messages, the voicemail messages were deleted. We sincerely apologize the Butlers were not adequately made aware of this possibility and are working internally to assure this information is clearly communicated to customers in the future."
A T-Mobile representative, Graham Crow, said the company is looking into compensating the family.
"We understand and we feel sorry for what the family is going through," Crow said.
But Butler, who works for a labor union, said compensation isn't enough. He's hired attorney Chris Crew to file a negligence suit against the company, demanding them to tap into archives and retrieve the voicemails.
"What I think is really going on is that they don't want to tell people they can recover lost data, because then everyone will want their deleted items retrieved," Crew said. "It will cost them a lot to do it, and it would be worth it in this case, but not for everyone that's lost their voicemails."
Crew said the family plans to file the lawsuit next week.
"I listened to it probably twice a week because I miss her so much," Butler said. "We just want to be able to heal and remember her voice."