Do they size tiaras to fit your head?

Ugggh I had a hair trial and the sample tiara they gave me to use which is supposed to be a duplicate of mine but given to me so I can get hairspray on it is too BIG for my tiny head. Now I don't know if I can get a refund or exchange it for a comb which will probably fit better. Does anyone know if Lilletes will help me with this? Did anyone else have this problem? I will be calling them shortly