Kingston — rude behavior

I went on nehru place kingston service center at skylark building 6th floor. When i gave my last yr purchased 8gb hyperxfury ram to the staff of service center he replied that it can't be reaplced bcz product have some junk on its tooth. Then i immediately rub off the junk from ram. Nearly only 1-3tooth have some junk on its tail. He rudely refuse to take it.
I only want to ask how is it possible to give back 1 yr used ram as clean as new sealed pack purchased ram. There might be some blackish tooth of ram because this is india.