Hi @mah_M_oud, sorry to hear about this. 
If you can't remember the screen lock on your device, I would recommend that you perform a software repair using Xperia Companion. Do note that this will delete all data stored on the internal storage of the device and remove the screen lock in the same process.
Since you can't unlock the device, a backup can not be created due to security reasons.
I hope that helps! 
