It sounds like you didn't actually have your account compromised at all. You entered her account information yourself and then she used that (a known scam) to lock the phone on you. By logging in with her infroamtion you essentially made her (if it even was a female) the owner of the device.
Your only recourse is to prove to Apple you are the true owner of the device and have Apple reset the device. Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. Do this online at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not detail what currently constitutes proof. Prior to this new online service Apple typically required the original receipt issued by Apple or an Apple Authorized Reseller and documented provenance (so typically it would be the original owner who does this, or a descendant with legal proof of ownership). This will give you access to the device but won't restore access to the account used to lock it. There is nothing that can be done to expedite an Activation Lock request.
Apple recommends you "Keep your receipt after you buy an Apple device" --> Keep your receipt after you buy an Apple device - Apple Support
The article What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support has useful information for selling a device but has no direct bearing on resolving this situation where you have been a victim of a scam.