NO REFUNDS FOR THIS SERVICE
These Codes come straight from manufacturer so there is no chance of error. Only possible reasons for codes not being accepted are the following:
Have to use realease method
Phone has been rooted (Un root it and restore original firmware)
Software has been changed from original version (for e.g Rogers S3 has been upgraded with a bell S3 software... To fix this you have to download the original Rogers S3 firmware back on to the phone.. this is a tried and tested solution)
Phone has been refurbished and the imei has been possibly changed (no solution for this and its a very rare problem)