Demi Leigh Mahon died from head injuries
Children's services in Greater Manchester have admitted there were failings in the protection of a toddler beaten to death by her babysitter.
A serious case review found phone calls from relatives and neighbours concerned about Demi Leigh Mahon's welfare were not followed up properly.
The two-year-old was killed by a 15-year-old boy while her mother went to collect a child benefit cheque.
Social workers knew the family but a protection plan had not been set up.
Gill Rigg, chair of Salford Safeguarding Children's Board, commissioned the investigation into the young girl's death.
She said the death was unpredictable and therefore unavoidable but there were a "whole range of issues that needed to be significantly improved".
Concerns about the girl's mother Ann Marie McDonald's drug problems were not dealt with adequately, the different agencies involved did not communicate enough and there were a lot of "missed opportunities" for intervention.
The report found Ms McDonald gave the social services misleading evidence about her drug misuse and there was no proper follow-up which resulted in the case being closed.
The girl's father Gary Mahon said social services did not do their job properly
Gill Baker, of Salford Children Services, said: "I am desperately sorry that we did not put better services in place for her [Demi Leigh].
"It is clear from the review no matter how well we co-ordinated our plans the tragedy that resulted in this child's death was unavoidable.
"But that doesn't take away anything from the fact that our services should have been better.
"We have to learn from this, we are not trying to shirk any responsibility for this.
"There should have been a better response and people involved should have taken things more seriously."
Demi Leigh had been living with her mother in a flat in Eccles. Her parents had split up when she was a baby.
The serious case review said there was a severe lack of information about the child's life, even though neighbours had rang to express their concern.
Grandmother Frances Gillon said she got no response from social services
The little girl had often been heard crying and at one point her mother had taken an overdose.
Both her father, Gary Mahon, and her grandmother, Frances Gillon, had contacted social services.
Ms Gillon said: "I made phone calls to them, the first time was three months and then three weeks before she died.
"I left information that we were concerned about the safety of the baby and they did absolutely nothing. They never even phoned me back to say that they responding to my phone call or anything."
Professionals did visit the home, but they did not always see the little girl to check on her condition.
Demi Leigh Mahon's father, Gary Mahon, said: "They didn't do their job properly, I don't know how many times they were called - it's just too late now."