Just a warning to everyone to not use MtGox. Sigh, I knew I should have stuck with BitcoinExchange.
What should I tell them? I mean I swear it was stolen from me. What can they do?
Everyone? There are far more traders not getting BTC stolen than traders claiming they have had BTC stolen. This sort of thing happens everywhere. Furthermore your title is sensationalist (MtGox clearly didn't scam you, you probably scammed yourself by having a shitty password) which leads me to believe you are lying in order to try get some sort of compensation.
Sorry if your BTC really did get stolen. That sucks. But what were you doing with 17BTC in your MtGox account anyway? Surely you've read all the reports from people claiming to have their accounts compromised.