Macbook Pro 2017 is locked by Remote Management

Hi there,

I am in a panic situation and I need some help to resolve this problem. I bought a Macbook Pro 2017 for my wife to upgrade her 2009 MBP from someone in the Craiglist. We used for a few weeks without any problems but all of sudden, a message from Remote Management from a company we have no ideas popped up and lock the Macbook asking for Use name and password. This MBP has no icloud or Apple ID associated with. Please help me to remove this. We (I and my kids) paid $1,050 with our saving money for 2 years in order to buy this for my wife on her birthday. Please see attached pictures so you know what I am talking about.

We really appreciate for your help.

Thanks,

Hahn