First, Jennifer Lopez’s Fiat ad was under attack when it turned out the parts of the ad featuring the Bronx native in her hometown were actually filmed on a soundstage in Los Angeles. Now the ad is back in hot water as a group of Bronx graffiti artists said Tuesday that Lopez and Fiat didn’t have permission to use their mural as a backdrop in the ad. The commercial features a mural tagged by a group of artists known as TATS Cru, who now say no one from the group was contacted about the use of the mural. “Everyone started congratulating us on the commercial and we’re like, what commercial?” said Wilfredo Feliciano, one of the artists in the group. He said they had contacted a lawyer. A spokeswoman from Fiat said the company is investigating whether the image was “appropriately secured.”