Why can't I unlock my xperia?

Please, I've set a pattern to block my smartphone. Now I'm sure I'm drawing the right pattern but I can't unlock it! I've draw more than 400 times potential patterns and none of them worked.

Okay, I'm human, lets suppose I forgot my password. When I click "forgot my password" and add my gmail account, it doesn't work!

I have some important data that I can't loose. Is there any way that I can unlock my Xperia z2 without loosing my data in the internal storage?
I have all the receipts and serial codes that came with the smartphone.