If you are lucky then flashing the MAIN firmware(but ONLY the MAIN) it will bring back your phone to life, and you will be able to save your contact list with MyPhoneExplorer. After you recovered the contact list, you can flash your phone completely: XS++ 3.1 Guide-Flashing, Customizing, Recovering
How to flash the MAIN only: follow the XS++ 3.1 Guide-Flashing, Customizing, Recovering guide BUT in 3) Flashing the firmware, Step 2. select the MAIN firmware only and press the flash button.
If something isn't clear, just ask;)