(CBS) — Mistakes with an order in a drive-thu happen all the time. But not like this one.

WBBM Newsradio’s Cisco Cotto reports.

READ MORE: Chicago Weather: Best Rain Friday Night

Debbie and Hans Wirth eat at McDonald’s every day.

Hans is a lung cancer patient receiving chemo, and the McDouble sandwich is about the only thing he says he has an appetite for.

On Wednesday evening, they went through the drive-thru at the restaurant on Biesterfield Road in Elk Grove Village.

READ MORE: Getting Hosed: A Look At The Universe Of Chicago Water, And Its Sometimes-Sordid History, This Earth Day

When they got home they opened the sandwich and found a dirty rag instead of a burger. They called the restaurant and were told they could get a replacement sandwich, but all they really wanted, they said, was a formal apology.

Hans Wirth says a manager called him Thursday evening to apologize.

The Wirths say they will continue to go to McDonald’s.

McDonald’s released a statement Thursday evening from owner operator Rich O’Keefe. “I take this matter seriously and we are currently looking into this claim,” he said.

MORE NEWS: Shuttered By Pandemic Last Summer, Guthrie's Tavern In Wrigleyville Has New Owner And Will Be Reopening
Hans and Debbie Wirth says this is what they found  -- a rag, not a burger -- following a recent trip to McDonald's. (courtesy: Wirth family)

Hans and Debbie Wirth says this is what they found — a rag, not a burger — following a recent trip to McDonald’s. (courtesy: Wirth family)