Dior Liquid Liner Faulty and no after sales Assistance

I purchased a Dior liner and it did not work from onset I took it back numerous times and I was unable to get assistance It’s been going on for over two years and I’m so fed up as the item was pricy, the consultant at gateway did admit that it was a manufacturing defect but would not let me even send it in for testing. I feel if this is the after sales service of Dior I will not be supporting it.