Alright, guess i'll give my version of how things went.
I knew about the condition of the RIS , that some inserts were stripped and some screws endlessly screws in etc...but its been a while i didn't handled the RIS, i also told him to give me some time to verify it more to give him a more complete description of the RIS. But he told me not to bother, to ship it ASAP and that it should be an easy fix by his gunsmith. But when he got it , I guess he saw that it was a problem that his gunsmith could'nt repair, he wanted a refund.
AS most of the items sold on these forums, it is sold AS IS, even if not clearly stated. He knew it was a used item and i warned him about it.
As my trader rating shows, i am an honest seller and i don't try to screw over people for a couple of dollars.
Thank you all for your time,
Payment : EMT is prefered , paypal ( +4 % ),