An eight-year-old girl died from sepsis after she was sent home from the GP twice in four hours, her parents said.
Mia Glynn, from Biddulph, Staffordshire, had been vomiting and complaining of a sore throat and bad headache for three days.
Her GP gave her antibiotics and said the hospital was too busy to help, but parents Soron and Katie Glynn called 999 later that night when Mia's lips turned blue.
She died in hospital with her cause of death ruled as sepsis caused by Strep A infection.
Her parents, who have spoken for the first time about losing their daughter, are now taking legal action over the tragedy in 2022.
“The unbelievable and unbearable pain we feel is unexplainable and unimaginable," Mrs Glynn said.
"Our beautiful healthy girl was the happiest, brightest, most loving and caring girl who smiled, danced, brought joy and love to everyone she met."
Mia started complaining of a sore throat on 5 December and her parents took her to see a doctor three days later when she developed a temperature and severe headache.
Later that day, Mrs Glynn took her daughter back to the surgery concerned over her condition and the doctor called a hospital for a second opinion.
The 37-year-old was advised to take Mia home as the hospital was full. She was sent home with antibiotics and was advised to give Mia fluids and ibuprofen.
Her parents called the ambulance shortly after 03:00 GMT on 9 December after Mia woke up with rashes on her arms and legs.
Mr Glynn, 39, said panic set in when Mia's lips turned blue.
"I said to the ambulance lady is [Mia] going to be ok, but they said they were doing all that they can and I knew then," he said.
"Shortly after that they started doing CPR," his wife added.
At hospital, Mia was given intravenous fluids and antibiotics but went into suspected septic shock and suffered a cardiac arrest.
Doctors tried to resuscitate her but she died around 20 minutes later.
Mrs Glynn, a self-employed hairdresser, said: "We’ll never get over the pain of losing Mia especially in the way we did."
“Our hearts hurts every second since Mia’s heart stopped.
"But we will always make sure Mia will be remembered in the most special way.”
Mr Glynn, an engineering teacher, added: “Seeing Mia in her final moments was awful.
"We feel so blessed that she was our daughter but are completely heartbroken that Mia was taken from us so soon."
The couple said their focus now was on raising awareness of the dangers of sepsis.
More than £40,000 has been raised in her memory through a variety of fundraising events and the family has donated more than £16,000 to the UK Sepsis Trust.
Investigation into care
Victoria Zinzan of Irwin Mitchell is representing the couple in their claim of medical negligence.
“Mia was a cherished daughter and sister whose death has had a devastating impact on her family," she said.
“Understandably her loved ones continue to have a number of concerns about her death and the circumstances surrounding it.
“Sadly through our work we see too many families affected by sepsis; with Mia’s death vividly highlighting the dangers of the condition."