Myphone was given a 4 number code that i dont know so im unable to use my phone

Question

The passcode on my phone was changed to a number I do not know. I am unable to unlock my phone

Answer 1

You will need to restore your phone and recover from a backup.  First you will need to erase and restore the device to factory settings:
You can restore the phone by completing a DFU restore.
DFU Restore:
1. Connect your phone to your computer
2. Open iTunes
3. Press and Hold the Sleep/Wake button and Home buttons simultaneously for approximately 9-10 seconds
4. When the screen goes blank, release the Sleep/Wake button and continue holding the Home button
5. the screen MUST remain black.  If the Apple logo appears while still holding the Home button you did not time it properly (either you released Sleep/Wake too soon or too late)
6. iTunes will pop up with a small window indicating you have connected an iPhone in recovery mode and can Restore it to recover it.
7. If the apple logo appears due to incorrect timing the Recovery mode message may still appear in iTunes, but you should simply dismiss it and try again from step 3.
Afterwards, you'll want to restore from backup.  If you use iTunes for backups, then your computer will ask if you'd like to restore the phone from backup after the process above completes and it is recognized as a blank phone in iTunes.  If you use iCloud for backups, then disconnect your phone after the process above and wait for the first-time setup screen to appear on the phone.  Select language, location, activate the device, and accept the terms and conditions; then choose to "restore from iCloud backup".  After you sign in with your Apple ID you'll see your backups and you can select one.  iCloud remembers that you had a password set but does not store the password in the cloud so when your phone restarts with your information on it it will prompt for a new password to be set.
If you did not have a backup on iTunes or iCloud, shame on you...  Also, your information is gone unless you're willing to pay hundreds/thousands of dollars to a data recovery firm to maybe get things back.  You get what you get and you don't get upset.