Pop up Kitchen sink waste

[ANGLER]

I was just about to install my new kitchen sink, to discover that a small 2mm fragmentl of end thread, had come off the the waste pop up base. I was unable to reattach it, due to fragment had disappeared. Possibly swept up by the Mrs.

Obviously this going to cause a water leak issue, when attaching to the trap..

Is there any chance of making a repair??
I've uploaded two pics showing the type of waste and a pic, before the fragment fell off

 

[PrenticeBoyofDerry]

Would be handy, if you could identify what item you have lost.

 

[ANGLER]

The missing section is on the bottom of the thread.

 

[23vc]

Cut the rest of it flush, reattach trap with generous washers/pfte/LSX ?

 

[PrenticeBoyofDerry]

Yes you would need level it all to the same as the damaged area.
Only other alternative is return it, they should replace it, if it arrived damaged.