The court heard that the woman's problems started in 2009, when she could not pay off her debt to unlicensed moneylenders (UMLs) and started working for them instead.
In July 2010, she was fined $60,000 under the Moneylenders Act.
Unable to pay the fine, she turned to borrowing from UMLs again. Then last year, she was told she had to pay up for a friend for whom she stood as a guarantor.
After she stole and sold a gold bar which belonged to her husband, they fell out.
She moved out of their home with three of her children, agreeing to work for more UMLs to pay off her debt.
That was when she started her harassment activities - vandalising debtors' homes and cars.
She also facilitated money transfers by helping to hand over ATM cards and doing bank transfers.
On one of these occasions, she took her 11-year-old son along and made him splash red paint on the door of an Yishun flat.
During submissions, Deputy Public Prosecutor Houston Johannus said this was "perhaps the most aggravating factor" in her case.
He also pointed out that she had re-offended while out on bail for an earlier series of loan-sharking offences.
She had been due to appear before the court on May 7, but did not show up.
A warrant of arrest was issued.
The woman was nabbed at home on July 22 and charged for another nine UML-related offences.
In sentencing, District Judge Low Wee Ping said the extent of her crime "puzzled" him because it was usually men who committed such serious loan shark-related offences, and that he was shocked she involved her young son.
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