Elina Tiumalu then sent messages to the teenager, repeatedly swearing at her and threatening to "smash your face" if Hayley texted her husband again.
Hayley later overdosed on her father's heart medication.
It saddened Mrs Fenton, of Rotorua, to hear about the significant rise in the number of suicides in the 15 to 19-year-old age group over the past year, especially because teenagers that age keep so much from their parents.
"We knew nothing about what Hayley was going through."
For anyone considering taking their own life, Mrs Fenton urged them to think about what that would mean for the ones that cared about them - to understand that their actions could drive family members to alcoholism and drugs or could tear apart a marriage.
"Just tell someone, tell someone what you're going through so they can help."