Q: activation lock is on

Take it and its purchase receipt to a physical Apple Store.

(143645)

If you forgot the Passcode:

https://support.apple.com/en-us/HT204306

If you forgot the Apple ID Password:

https://support.apple.com/en-us/HT201487

Take the phone and the original proof of purchase to Apple if you can't recover the account you used to sign into iCloud and turn on Find My iPhone.

Are you sure that you have never used a different Apple ID in the past? Id you look at the partial ID listed on the page, does it look familiar? If not, then you can make an appointment at the Genius Bar of the nearest Apple store, bring the device, a copy of the original purchase receipt, and your identification and ask Apple for assistance.