My parents and sister haven't come home yet!?

my parents and sister went to this jewelry store so she could get something she needed there and get her necklace fixed and they left about 3 hours ago and the jewelry store is about 20 min away so i understand tht thry have been gone for 2 hours but they have been gone for 3! now turning into 4! and i have called my sis's cell about 5 times before i left a message becuz by the 3rd call she usually picks up but hse didnt! i just called right now too! what should i do and i dont want to contact the police unless they dont come by 8 so wht should i do?!