Hi user, im sorry for the issues your having. Are you being asked to put in the password for your Gmail account? you will need any passwords requested by the phone in order to access the phone. You can have the phone unlocked but you will need to have your proof of purchase with the IMEI on it.
Just head over to findmymobile.samsung.com and use your Samsung account credentials to sign in. If the device is registered to your account it should locate the device and give you some options of what you can do with your device, one being to disable the security on the device.
If you are unable to access the phone through findmymobile the next step would be to factory reset the device. I would recommend taking your phone to your carrier or a Samsung walk-in center to have someone do this for you. You can locate walk-in location with a Samsung tech by using the following link. https://www.samsung.com/us/support/service/locations/
Great! currently right now there are few locations where you can go to have your phone unlocked. If you would like to look up some locations to get this done you can use this link.
If you are referring to the password set up in Security on the phone, I would recommend going to findmymobile.samsung.com. If you have the device registered to your Samsung Account you can use the credentials to log in to your Samsung Account to log in to findmymobile. Once signed in you would be able to remove the lock.
