By Maria Medina

GILROY (CBS SF) — County leaders in Gilroy presented a woman with a big check this Christmas Eve after she discovered a multi-million dollar property tax mistake.

“You know, when government makes a mistake, we have an obligation to fix it,” Tax Assessor Larry Stone said.

READ MORE: Construction Accident Triggers House Collapse In Lafayette

Just four months ago, Erin Cerdan was struggling to make ends meet. Her property taxes went up more than $300.

She spend months pushing county leaders for answers, and discovered that the county had overcharged he for property taxes for more than a decade because her home had never been reclassified as low income.

She also found out that she wasn’t alone.

READ MORE: Veteran Falls Victim To Phishing Scam, Loses $19,000 From Chase Bank Account Meant For Daughter's College Education

“My neighbor here, you know, said to me about making a choice between groceries and paying your mortgage got me in action,” Cerdan said.

Because of Erin, more than 200 homeowners will get a refund, with dozens of checks being sent in the mail over the next few weeks totaling more than $3 million.

Erin’s refund totaled nearly $30,000.

MORE NEWS: 'Makes Americans More Free': Dana Zzyym Issued 1st U.S. Passport With Gender X Designation

Erin is the first in the neighborhood to receive a check, but says her true gift this Christmas is knowing that her husband can quit his second job they had needed to make ends meet, and that her neighbors can keep their homes.