Hi,
If a portion of the headphones are stuck in the jack you can try to delicatly remove them using this tool [product|IF145-333] . However you need to be careful doing thiis. If you cannot remove the jack using this method then the headphonje jack would need to be replaced which is this part [product|IF316-003] .
It might be worthwhile seeking out your local repair shop if you do not feel you are able to preform the repair yourself.
Kind regards
Matt