items given at the time of engagement but marriage not happe

It will be double edge sword which can hurt you more badly than your imagination, better forget it. 

You can take others opinion but I gave my opinion 

The best course is to try  through mutual friends and well-wishers!

If the marriage is being called off then both parties may preferably return respective items of each other, amicably.

Try to resolve with help and intervention of elders of the family, well wishers, mediators, reputed person…..