That is so sad. How long have they had her? As MyFairLacy said- she is your dog and you have every legal right to claim her. I would get your paperwork together and tell them you are on your way to pick her up. If they have a problem with it the police can get involved. Good luck!
__________________
"If you have men who will exclude any of God’s creatures from the shelter of compassion and pity, you will have men who will deal likewise with their fellow men." — St. Francis of Assisi, 1181-1226