I have purchased a macbook Pro few months back when i bought that Macbook that Mac wasn't Attatched with any apple id but now it's on activation lock and shows me someone else's id

i have purchased a macbook pro from a local shop in dubai firstly it was open and not attached with any apple id just like new i setup the Macbook with my apple id but after few days i tried to upgrade my mac and it suddely went on Activation Lock and after that it doesn't even show me my Apple ID to Unlock and shows me someone else's Gmail Account i am not familiar with that acoount and tried to contact apple support for removing that and submited the purchasing proof but it still not activated and i am not getting any response from Apple support.

so i wanna know is this normal or what can we do something on this scenario is there any possibility to do that or reactivate my macbook