Try to complain on the chatbox on the site to let others know, at least you'll attract attention to yourself and hopefully they'll see you as a nuisance and will just pay your withdrawal just to get you to shut up 

Tag them on twitter as well, https://twitter.com/Liqui_Exchange is pretty active on twitter. Comment on their thread here: https://bitcointalk.org/index.php?topic=1557900.0

I have never had a negative experience with Liqui to be honest. Have always been one of the smoothest exchanges to deal with although their withdrawal fees are a tad too high. You should get a response from them, if you do as i told you to.