I am not able to get back to my iPhone 6

It sounds like you may be encountering this issue -->

"Activation Lock for iPhone, iPad, and iPod touch" is a security feature with an added aspect of possibly deterring re-selling of stolen devices. To learn more click here --> http://support.apple.com/HT201365

For an individual to remove an activation lock this absolutely requires the information for the account that applied the lock. Click on this link to learn 'How to remove Activation Lock' --> https://support.apple.com/HT201441

If you do not know the required information and you are not the original owner, get the owner of the account to remove the lock or return the device for a refund or recycle it. The device is otherwise useless to you. If the owner is unknown and has not provided contact information as a message showing in the login screen, there is no way to contact the owner unless the person who gave you the device knows them.

For help dealing with lost Apple ID or password:

• "If you forgot your Apple ID" [this is likely an email address you are using or used in the past] click here --> https://support.apple.com/HT201354

• "If you forgot your Apple ID password" click here --> https://support.apple.com/HT201487

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 state what currently constitutes proof. Prior to this new online service Apple typically required the original receipt issued by an Apple Authorized dealer and documented provenance (so typically it would be the original owner who does this, or a descendant with legal proof of ownership).