How to disable Encryption
To disable encryption you need see to that you comply with the following things:
a) Your battery must be fully charged to a 100%.
b) You must have an android phone
c) Brains.exe (Kidding! Patience)
Since, you did not tell me your model so I am considering that it is Android
Step 1: Backup your data (If you know to decryption key )
You can do this by installing TrustGo antivirus from the Play Store, Its Free and Legal! and sign up for an account
Step 2: Use someone's WiFi or your Internet Connection to Back Up the Data
Step 3: Check the Data on the TrustGo Website (Only Contacts and Messages will be backed up)
Step 4: Use your Google Drive to back up your data (15 GB of Free Space should do it)
Step 5: Factory Reset your phone (Hard is recommended)
Step 6: Restore Data (TrustGo) by installing the app and signing in and restore
Step 7: Restore Data from Google Drive
Step 8: Volla!