ST. LOUIS — Lucas Santos said he hopped in his car, left his home in south St. Louis and stopped by his neighborhood gas station last Tuesday before heading to work.
"I got E-85 at the Circle K on Jamieson," Santos told 5 On Your Side.
He said he drove his 2018 Ford Nicosport onto the interstate, but within minutes, he ran into a heal of headaches.
"I kid you not, in 10 minutes, my car started breaking up, making noise and acting weird," Santos said.
He said he made it to an auto body shop and learned his tank wasn't full of unleaded gas but diesel. He said a manager at the Circle K even confirmed it.
"He said it to me. He didn't like message me or put anything in writing, so I started contacting Circle K," he said. "I checked their website, their social media to see if I could get any answers."
He wasn't the only disappointed driver looking for answers.
"I've been without a car now for a week," Melanie Jack said.
Jack said last Thursday, she, too, filled up her brand-new car at the same gas station with what she thought was unleaded fuel. However, both drivers are now stuck with bills from what they say are their diesel-damaged cars.
"I'm sitting on $600 so far, but they still have to check the spark plugs, and they might need to open my engine," Santos said.
"I'm going to be at at least fronting over $5,000. My car wouldn't even start and couldn't roll onto a tow truck, " Jack said.
One week later, the dismayed drivers are still waiting to hear from Circle K.
They said they received text messages from the company's apparent insurance adjuster on Wednesday morning.
"We can't get clarity from Circle K, so that 's making the frustration build," Jack said.
"I just hope my car doesn't need any more repairs," Santos said. "I do know that I am not going back to that gas station."
5 On Your Side's Robert Townsend stopped by the gas station for a response to the drivers' claims and apparent fuel mix-up, but workers told him to "call their corporate office."
Townsend did several times and even emailed the company, but as of Wednesday night, he hadn't heard back from anyone.
To watch 5 On Your Side broadcasts or reports 24/7, 5 On Your Side is always streaming on 5+. Download for free on Roku, Amazon Fire TV or the Apple TV App Store.