Apple ID masked in Activation Lock

It's not the same ID: the ID isn't displayed, just a hint (the askerisks are used to mask the letters in the ID), and a large number might fit what you see there. When the Activation Lock is set the phone can be used until it is erased or reset: then the lock kicks in. It's designed to render a stolen phone useless and obviously if there was an easy way of getting round it there would be no point in having it in the first pace.

In order to proceed your Uncle needs to provide you with the ID and password used to lock it. If he's forgotten them, and is the original owner, and has the original purchase doucments showing the serial or IMEI number, he (not you) can request an unlock from Apple: https://al-support.apple.com/#/additional-support

Failing those two options there is no way you will be able to unlock the phone.

Did you buy the device used? It may belong to a former owner.

'Activation Lock for iPhone, iPad, and iPod touch' is a security feature that's designed to prevent anyone else from using an iPhone, iPad, or iPod touch, if it's ever lost or stolen. To learn more click here --> http://support.apple.com/HT201365

For an individual to remove an activation lock 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 the device. 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.

It is not a placeholder account.

You have a used phone that is locked to the previous owner's account.

Talk to whoever you got it from.

If they can't or won't remove the lock, get your money back.

If you can't do that, turn it over to the police. It's probably stolen.

That's the Apple ID (well, at least a part of it) that was used when the phone was set up.