It was wrong to give it, if it was a precious metal you should have melted it to change it into something else, or destroy it and dispose of it otherwise.

Two years ago, I  found some necklace of cross at home, I don’t know how it got there, maybe in childhood my family found them from somewhere. But we have given that bag of necklace to one of our Christian neighbour.I feel like me and my family had commited a major sin.What should I do? I did repent to Allah but my heart & mind are always occupied by this incident.