existing door mortise and keeper help

existing door hardware does not latch. Not sure if just the hard side is all that needs to be changed or both pieces...

I had ordered a replacement (not correct)

Item # 82-211, it is too wide and too tall even though site said 3" x 3/4"

I definitely think I need 5/8" wide and the holes at 3 9/16" appears to be good (if width is

Need some assistance getting my cheap doors to at least lock.

Thanks,

Dave

entire piece is 4" long
Insert is 3 1/4" long x 1/2" wide

I guess I am not really a quick learner...