Car Hop Illegal. Incompetent. Refusing to help or comply with department of revenue. joplin Missouri

I purchased a car from carhop around 2 years ago. I returned the car within 2 days due to its faulty condition. I was later contacted by the missouri department of revenue stating that I owe sales tax on this car this I do not own. I have contacted car hop dozens of times to request that they contact the department of revenue and correct this matter but they have not complied. I have also advised them of the forms they need to submit to the department of revenue to resolve this matter and they continually claim they have submitted the documents, but the missouri department of revenue states they have not received these documents and that this is a common issue with car hop. In the last 2 years I have been unable to resolve this issue.