Tell her you’re calling the cops if you don’t get your dog back. I hope you have something in writing.

Let her call the cops, you should be calling them anyway since she literally stole your dog

If you left your dog with her, it's not legally theft, it's a civil offense, and you could sue. Police will probably have a chat with her as well, and there's a strong suspicion that there might be fraud (if you paid her for the service) or animal cruelty having gone on. I'm sure if you get a police owner with a pet, they'll be on your side. That woman deserves a special place in hell, since pets are like family.

Police didn’t help me when my Senegal was stolen this way. I even had proof of ownership.