Update will help retrieve those data but remember since the phone was originally locked to vodafone, updating the firmware may lock the phone back

Okay so I had a 3 phone (i dont know if thats worldwide, for anyone non-Australian, but stick with me) which I lost and I just bought the same thing again cept on Vodafone. Now before when I had it on 3 there was an icon for the Planet 3 service, but now there's an icon for the Vodafone Live service instead. This phone was locked to Vodafone but I just unlocked it and put in my 3 sim card, and the vodafone live icon is still there, it hasnt changed. So my question is: How do I make it like it was befoe, its possible too right?

Also I just deleted like all my themes/ringtones/pictures that seemed like the kinda standard stuff that comes with every phone cos I tried to fix my problem with a master reset. Is there ANYYY way to undo that? Will updating restore all the themes? I cant seem to update my phone either? How in the f do you update? Keeps saying update failed?