But on your Facebook you said you've already called the police.
Is your mobile number in the public domain like a personal business site?
He's got it on his Facebook page, at least to friends.
To be honest, I'd just ignore it and put it down to drunken idiots. I doubt the police will do anything, and you'll just worry yourself more by dwelling on it.
Get rid of personal details like that from online and carry on with your life.
Definitely someone off of OcUK
If this is a prank then it's a horrible one.
Personally I don't know anyone who would think about doing this, take it seriously and move somewhere safe. Including your girlfriend.
Good luck, I hope you find who has done it.