I tried to play her few times, I am surprised of how short range her Q and W are? Basically to do damage, your opponent must be melee or otherwise you have to all-in. Also, pretty bad skaling for her abilities. I bought her because of nice mechanics but overall it feels like she isn't worth of time.
Indeed, she's hard to play because of how short range she is. This gives her a good niche against champions like 
that have to get within her range in order to do any damage. She also works well with 
that give health in addition to some juicy AP. Lastly, 
is really necessary on her.
She can permaCC and initiate teamfights with her dash. Imagine, if she was long ranged... Every champ has needs some kind of weakness - range, CC, damage, anything. Her scaling is good enough. If they buff her dmg, they have to nerf her root, slows or stun.
Looking at your match history, I only see one game of her. It's most likely that you just aren't comfortable with her yet. However... http://matchhistory.eune.leagueoflegends.com/en/#match-details/EUN1/1663526398/30003253?tab=overview
Your Vayne and Vlad both got destroyed, so it may not be the best game to gauge yourself, or that champion, off of.
I'm assuming you were playing her as support too, which "can" work, but isn't recommended. If you're going to play her, take her mid where she belongs. Morello's, Rod of Ages, Hourglass, Abyssal... all really good items on her.
My advice: Play her more. See how you do, and come back with an update of your experience and any questions you may have.
Lissandra is a decent champion, but isn't really in meta right now, as there are more viable picks. Apart from that, she is a good champion, with a clear strength in being able to do damage and lock someone down.
