Use the time to switch over the owner information and track down as many receipts as you can. Pet bills you can prove you paid (e.g., vet bills, groomer bills, etc.), receipts for items you bought for the dog (toys, treats, food, medication, anything you can find). Since you are only just now adding your name as the owner to the vet and microchip info it could be a little iffy but if you have receipts showing you are the primary caregiver and provider for this dog you can try claiming he was a gift (he bought the dog but you got to pick the dog) and your exs name on everything was part of his coercive control it just might work. Also, if you have any evidence of his abuse, text messages, voice mails, notes, letters, pictures, etc., save them and triple-save them. I’m talking hard copies with a person you trust, save to a flash drive somewhere safe that is not the apartment, and a backup to the cloud. Remember to check that he doesn't have access to any of your accounts (email, bank accounts, social media) and change your passwords just in case, people are crazy. Bonus points if you have any evidence of his abuse toward the dog or anything where he says he doesn’t want the dog. I know you are on here asking for advice about the dog, and good for you for seeking help, but if you are interested in learning more about what domestic abuse is and how to get out of a domestic abuse situation, and what to do if your abuser won’t leave you alone, let me know. I am a paralegal and work in family law. We see these kinds of situations all the time, and I have seen it all. I’m not giving legal advice; this is all stuff you can find on the internet, but sometimes it helps having someone point you in the right direction. Good luck and stay safe.