I push a button and know I can't open my boot

need more info to help

Don't forget that GS300 has a security lock near the pull button for the boot. You lock this when you are leaving the car unattended as it prevents people breaking into your car to get access to the boot. So you may have locked this and therefore you no longer have remote access to unlock the boot from with in the cabin. Put your key into the keylock near the boot remote button and unlock it. You should now have access to your boot again.