My HDD is locked and wont unlock

Hi, I have a similar problem: can’t unlock a WD Passport Essential that I NEVER LOCKED! Never used any lock or password. While listening to my iTunes music on that disk, the music stopped suddenly, device was locked as I found out. No help so far from any local technician, 10 supporft mails from WD online support keep repeating they have no master password, I need my password… nonsense… Now finally, in this thread, after a lot of forum googling, I might have found a hint: I dont know the term FIRMWARE but I assume it is something like an operating system update? If I remember well (but no 100% guarantee) there WAS a WD update request while I was working (multitasking: music, editing photos, reading online news etc). I THINK I just clicked ok. The message that ‘this sometimes happens after installing new firmware’ gives some hope. Apparently it happens SOMETIMES, because my 2 other (500GB) WD’s have no problem, only my 1TB one. But more important is the ANSWER: how to get rid of the problem? Any help?