Reset my firefly GT200 mobile phone - Samsung SPH-i500

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Viking here,
If you did not change the passcode you might try 1111 which is a standard passcode. If someone put a different passcode in, you are going to have problems. I am not familiar with your cellphone, but let me know if this works. Passcodes are usually hard to locate just for the reason they are placed on the phone. Let me know if this works for you. If so, please leave feedback for me. Viking

http://www.att.com/esupport/article.jsp?sid=49237&cv=820

you need to reset the phone to factory settings
there is no other way
however its done by cable/pc software or key presses
you cant get past a password in an easy way... or it would not be much use..

so.. reset the phone then
most providers have a text number you access
once you send it a text it will send back the WAP etc settings packets
you then install

once you do this
access the phones update and update its firmware and apps too the latest

then start to build your phone again
if you have as you should do your contacts lists stored on the simm
then simply take the simm out
reset the phone too factory settings
then place back the simm

if you loose photos etc tough you've lost them....

1. Before you reset your Android One, see options for backing up your data
2. On your mobile device, open the Settings menu .
3. Under "Personal," touch Backup & reset. You may need to enter your pattern, PIN, or password.
4. Under "Personal data," touch Factory data reset.
5. Read the information on the screen and touch Reset phone.
6. If you have a screen lock, you'll need to enter your pattern, PIN, or password.
7. When prompted, touch Erase everything to erase all data from your device's internal storage.
8. When your device has finished erasing, select the option to reboot your device.

Instructions

• 1 Press and hold down the lock button on the Firefly phone until the screen says "Enter Pin."
• 2 Press the "Enter" button to begin entering the PIN number.
• 3 Press the right arrow button once. You will see the number one.
  
• 4 Press "OK." You will see an asterisk on the top line.
• 5 Press the right arrow button twice until you see the number 2.
• 6 Press "OK." You'll see a second asterisk symbol on the top line.
• 7 Press the right arrow button three times until you see the number three.
• 8 Press "OK." You'll see a third asterisk symbol on the top line.
• 9 Press the right arrow button four times until you see the number four.
• 10 Press "OK." You'll see a fourth asterisk symbol on the top line. The phone will unlock.
• 
  Read more: http://www.ehow.com/how_6361971_unlock-firefly-cell-phone.html#ixzz309pjkqds

ser.mom pahelp nmn sa firefly mobile s60 hangerz ano po gagawin ko po?

Sounds like you have not registered the new sim card with Customer Service. Call them.

Im sorry did you resolved your problem?
I have same problem (((?

contact AT&T customer service @ 1800 331-0500 and ask for an subsidy unlock code for the phone be ready to give the IMEI to Customer Service