We believe in unicorns and ghosts, but someone voluntarily letting a city keep her tax refund? Yes, such a person really exists, but somehow her act of goodwill toward the city of Detroit has been turned into an ordeal of vastly annoying proportions. The city now claims that she actually owes it $5,300. Good thing she’s kept up on her personal paperwork.

The woman thought she’d be doing a nice thing by letting her beloved, yet struggling city keep her 2011 refund. But instead, the city’s income tax division followed that up by sending her a letter stating she owed $5,296 in back taxes and interest dating back to 1999, reports the Detroit Free Press.

The city messed with the wrong resident, as the woman has a degree in accounting and as such, kept way more documentation than your usual tax payer. She claims that instead of owing Detroit money, the city is actually due to pay her $416 she never received, in addition to the $500 refund she was prepared to let it keep.

“What I would consider as doing a favor made out to be an invitation for harassment,” she told the paper, adding that at least she was prepared.

The city had documents listing a Social Security number that wasn’t hers and also information that she was married for certain years when she was single.

“I was upset, but I knew I had records,” she said. “I made copies and the next day went to the post office and mailed it off.”

When that didn’t resolve the situation, she went down to the city tax department in person to speak with the workers who were sending her letters. She asked what was needed, made copies at home, and handed over anything and everything that could possibly be needed to show she was owed money, instead of vice versa. The situation appears to remain unresolved.

A city spokesperson declined to comment on a specific case, but noted that a resident has 30 days to write a letter disagreeing with a tax bill. This incident occurred in December 2012.

“I work too hard for every little bit of my money I make to just give it to you because you’re being lazy,” says the woman. “The system down there is so antiquated that there’s no system. They’re basically doing it on a 10-key calculator.”

Consumer watchdog: Detroit turns $500 income tax refund into a $5,300 bill [Detroit Free Press]

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.