That's a bit "off-topic".
However, as far as I am aware, with the right software, all blocked or barred phones can be reset, but that doesn't have much to do with the data files. You can access data files without any mobile phone access at all - take out your SIM (so, no calls) and you will still be able to view all your files.
Even if you remove the SIM and delete all the files, unless you know what you are doing, the files on the phone's internal memory can be recovered.
You might want to buy an SD card (mine's 16Gb and cost £1
and set all the default saves to that. It means that when you sell the phone, you take out the SD card with your files and stick it into the new phone.