Grandma necklace

Assalamu Alaikum Warahmatulahi Wabaraktu

My grandmother passed away almost 20 years ago. My mother recently informed me that my grandmother had a gold necklace from maybe after marriage. She had never paid zakaah on this necklace back then. my mother says that it was due to insufficient islamic knowledge. A few years ago my mom’s sisters gave my mom the necklace. Since the death no zakaah has been paid on in either and nobody wears it too. My mother is now concerned about this situation. What should they do with regards to zakaah and to the necklace…can someone wear it if there is a debt of zakaah? They do follow the Shafi’i madhab.

Jzaakallah