All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Hence, your husband was categorically wrong by selling your gold jewellery without your permission. You have the right to demand your jewellery back and if he refuses to return them, you can refer the case to the concerned authorities responsible for handling disputes between Muslims in your country.
If possible, try together to reach a mutual understanding and solve the problem without referring the case to the Islamic Centers (or the concerned authorities). You can also seek the mediation of judicious and respected members of his family or yours or one of his friends, for instance, whose advice you believe will be accepted by your husband, if necessary.
Allaah Knows best.