Two people, including a six-month old baby, have died after the 911 emergency calls operation in Dallas, Texas was swamped with so-called “ghost calls.”
She dialled 911 three times but was reportedly placed on hold for a total of more than 40 minutes and eventually hung up.
Brandon was taken to hospital by his mother, Bridget Alex, but died without regaining consciousness.
In a statement, city authorities said when the call takers called back, they could not reach the sitter.
“I want them to take responsibility of my son’s death. That’s what I want them to do,” Ms Alex said.
“Because at the end of the day, my son was still breathing, but had y’all come out like y’all were supposed to, my son would still be here in my arms,” she added.
City officials admit that since November, there have been sporadic spikes in the number of calls to the call centre caused by T-Mobile customers.
Operators are forced to call back every number that registers as a hang-up to verify whether emergency assistance is needed and, if no one answers, police will have to be dispatched to the scene.
T-Mobile is the only carrier experiencing the ghost calls, and no other city in the state has had the issue.
The city saw a spike in calls at the 911 call centre on Saturday at the same time as the babysitter, who has a T-Mobile phone, was trying to get through.
It is reported 442 callers were put on hold for an average of 38 minutes that night.
Dallas Mayor Mike Rawlings said: “It’s unacceptable that it happened and we’ve got to make sure it never happens again.”
The CEO of T-Mobile has promised to send the company’s top engineers to the city and leave them there until the problem is fixed.
Brian Cross, 52, died after falling unconscious one evening earlier this month and it took his partner, David Taffet, 20 minutes to get through to a call taker.
“I don’t want to start hearing about more people dying as a result of people waiting to get through for help,” Taffet said.