When the girls became financially dependent on the woman and began to demand money from her, investigators say they were asked to leave.
In April, police say the girls attacked the woman after she refused to give them money.
After spotting unauthorized purchases from her bank account, the woman froze her account.
According to police, the teens, with the assistance of another 16-year-old girl, an 18-year-old woman and a 27-year-old man, forcibly confined the woman and drove her to multiple financial institutions to get loans.
An employee at one of the banks called police after noticing the suspicious interaction.
Police say officers were able to find the group at another financial institution and arrested the five suspects.
All three 16-year-old girls, who cannot be identified under the provisions of the Youth Criminal Justice Act, have been charged with robbery, forcible confinement and three counts of extortion.
One of the teenage suspects is also facing assault causing bodily harm and possession of property obtained by crime under $5,000 while a second 16-year-old suspect has also been charged with assault causing bodily harm.
Toronto resident Alexandria Batchelor, 18, and Brampton resident Gilbert Monney, 27, have each been charged with robbery, forcible confinement and three counts of extortion.