These days, I've been contacting Sony by mail.
In the end, I couldn't get my refund because of the Refund Policy (I have already downloaded the product). Fortunately, I didn't need my DOB to prove the account was mine. But still, that DOB Bruteforce would be very useful!
I even asked Sony if giving me the same DLC but the one from region 1 was possible; but they said they can't.
In conclusion, I lost my money
Anyway...
Thanks to all of you that tried to help me!