CHICAGO (CBS) — Every day new campaign ads are popping up from the candidates for Chicago mayor.

The union that represents window washers said mayoral candidate Susanna Mendoza needs to come clean about her record on labor.

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The organization put out a new digital ad that claims Mendoza deserted them while on strike. But are the allegations true? Here are the facts.

A new digital ad from SEIU claims Susanna Mendoza chose to support one of her donors rather than window washers last year during a 17-day strike.

It can’t be called a sellout but it looks to be true because it seems a calculated choice. Records show since 2014, Mendoza accepted $30,000 from Neal Zucker, owner of Corporate Cleaning Services, the city’s biggest window washing firm.

That includes $10,000 after the strike ended in September and another $3,000 donated on Christmas Eve.

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The 200 window washers got plenty of support from Democratic politicians, including Chicago Mayor Rahm Emanuel, Governor-elect J.B. Pritzker and 30 aldermen.

Mendoza claims, due to her relationship with Zucker, the union asked her to broker a settlement, but later told her to butt out. However, SEIU insists Mendoza told them, the window washers’ demands were irrational.

Meantime, the SEIU is definitely standing with mayoral candidate Toni Preckwinkle. She received a half-million dollar donation from the union on Wednesday.

Mendoza insisted the contract deal she tried to put through would have paid window washers more than the contract they eventually signed.

Still, after the window washers flap, Mendoza received no further contributions from the SEIU. However, Mendoza has received big bucks from several other unions, including $500,000 from the laborers union, $122,000 from the Illinois Federation of Teachers and $110,00 from the operating engineers.

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