Worst customer service ever ! When I purchased the...

Worst customer service ever ! When I purchased the car 3 years ago at 69,997 km from CMI Toyota used-car dealership, no one told me that the 70,000 km service had not been done, and no one suggested to do it. Now 3 years later I am losing money when selling the car because the 70,000 km service stamp is missing !!!!!!