LabCorp review: Fraudulent billing

I made an appointment in Sept 2024 for bloodwork and pre-paid through Walkin labs. In Nov 2024 I received a bill from LabCorp for $224. I called Walkin labs who confirmed they paid for the bloodwork. I then called LabCorp and told them that I did not owe them anything because it had been paid. They promised to remove the charge. Then last week 8/30/25 I received the SAME BILL for $224 dated Sept 2024! I called and told them I did not owe them anything because I cleared it up LAST YEAR! They said a supervisor would call me back. NO ONE CALLED ME BACK! This is fraudulent billing!