I'm so sorry for your loss DogBuddy. How very distressing this whole situation must be to you. I can't for the life of me imagine why they would have sent you an empty urn after they had lost the ashes. How cruel. Do you still have his collar? I would frame the collar with his pawprint and mount it somewhere as a special reminder. Hopefully in time your wonderful memories of your beloved pet will help you to find some level of peace. Remember that no matter where his ashes are, his spirit is at the bridge, and he will wait to be reunited with you, knowing that you loved him as no other during his too short time here on Earth. Please find peace within your heart. You boy would want that for you.
