I finally contacted Samsung and this was their response:
Dear June Barbosa,
Thank you for contacting Samsung Customer Care.
The issues you are experiencing are being caused by a software glitch on the handset. A hard reset will be the only way to solve these issues.
There are two ways to back-up your handset, the first way is to a computer and the second is to a SIM and SD card.
To back-up the handset to a computer you will need to use a program called Samsung Kies. I have provided the download link below and a video tutorial showing you a step by step guide on backing-up the handset.
If you have already installed an earlier version of Kies that will need to be uninstalled first. Once you have uninstalled the previous version, restart the PC and install the current version of Samsung Kies.
Samsung Kies download:
Below is a tutorial for Samsung Kies 2. This demonstrates how to use some of the features of Kies 2.0 including how to update the firmware for the handset.
You are also able to back-up Contacts to your SIM card and you are also able to back-up Photos, Music and Videos to your SD card.
To back up your contacts to your SIM card, please follow the below steps.
Contacts -> press the Menu key -> Import/Export -> Export to SIM card -> Select all -> Export -> Ok
To back up Photos and Videos that you have taken from your camera to your SD card, please follow the below steps.
Applications -> My Files -> DCIM -> Tap and hold on the Camera folder -> Copy -> Tap on external_sd folder -> Paste here
To back-up Music to your SD card, please follow the below steps.
Applications -> My Files -> DCIM -> Tap and hold on the Music folder -> Copy -> Tap on external_sd folder -> Paste here
Once you have backed-up any important data on your handset you will be able to perform the hard reset. To perform the hard reset you will need to enter the following code into the Dial/Key pad of your handset.
Hard reset code: *2767*3855#
If you have any further enquiries, please do not hesitate to contact Samsung Customer Care on 1300 362 603.
Thank you for contacting Samsung.
Samsung Customer Care
Mobile Phones | Televisions | Notebooks | Refrigeration - SAMSUNG AU
So the reset was done....I now have a lock screen...but it still gets hot, drops calls and freezes. I will NEVER buy another Samsung!