How To Change CSC Samsung s8500 without Flashing

Before you flash their is another way to debrand without flashing and keeping the same firmware.
Enter *#5239870*# to enter admin mode
Choose "Pre-configuration"
You'll be prompted for an operator code. click on the field then Enter: *#27236*#
You'll then be at the CSC Pre-configuration screen ... Here one can choose which provider the phone belongs to..

Depending on the CSC code you will see:
KOR (KOREAN – OPEN)
VMA (Virgin Mobile Australia)
OPT (Optus)
TEL (Telstra)
H3G (Three)
VDF (Vodafone)

If you only see
KOR
VMA
You can switch it to KOR which makes your handset generic, it will remove most of the Virgin spam.
Make sure you back up all your data if you use this method as it will reset the handsets settings.