Chain repaired but missistore lost the pendant.

My gold chain necklace was broken so we brought it in for repairs at AMERICAN Swiss in Woodlands Boulevard. When the chain was repaired they called us to receive the necklace but when we did the pendant was missing. The pendant is a small gold Star of David. <br> <br> The store staff said they would then let manager staff know and call us when/if they found it. They have now gotten back to me and told me I have no proof that there was a pendant and that I would have to buy a new pendant? This is completely not on and I am considering taking this higher to a court of law as that pendant dates back to pre- world war 2 era and is very important in our family.