request for the unlock code for Sony Xperia E


you are most kindly asked to provide the clean and workable code for decoding the cell phone device Sony Xperia E which is presently being locked by Telenor Serbia GSM and mobile provider in Serbia.
The device, ie. smart phone is operative only with Telenor SIM card (locked) even after the contract has expired. The code that has been provided by Telenor Serbia for unlocking the device is not accepted/recognized as the true code for unloking from Telenor GSM and registering with other GSM using other than Telenor Serbia SIM card.
This should not be the case, but has appeared.
Could you possibly provide to me a code for unlocking the device from Telenor GSM provider in Serbia, so that I can rightfully use SIM card from another provider in the same device, at my rightful convenience.
The IMEI of the device is 359608057391341 registered in Serbia.
I thank you for your kind attention and await for your feedback via e mail on the prompt basis, sent to my e mail address registered with your good selves.