I have i phone 4,the apple id is from the previous user.I don't know him to contact about the user ID.He erased all data from the phone,now its without nothing on the screen,it's like brand new one.How can I log into the phone without his ID

Welcome to the Apple community yllazemi.

Unfortunately, you cannot do very much with your phone unless you get assistance from the previous owner, they should either provide you with the password to unlock it or remove their account from the phone entirely remotely through iCloud.com> Find My Phone.

same thing happened to me...it's been 3 months now...i can't use my iPhone 4...i can't even contact the previous owner since the notification screen only give me "n•••••@y•••••.com"...what am i supposed to do? could you (apple) help us out by giving at least the complete email address from the previous account so we can contact the previous owner? i bought the device legit & legally, i also checked the IMEI, it's not stolen or report missing before i bought it...it is my mistake to forget asking about the id & password...

Nobody here can give you the contact info for the previous owner, you must do it yourself.

Yup, but it's worth to try though😝...with all these related topic, maybe (just maybe) apple would provide a win-win solution to overcome this problem *peace

Good luck.