First, you're assuming that everyone is here to find or be language partners. That isn't necessarily the case; a lot of people are probably only here to find teachers and (maybe) occasionally participate in the community. Second, were all of these messages to people who are studying Arabic? Because if you chose people who aren't, then they aren't likely to get much out of partnering with someone who speaks a language that they aren't learning. Even if they are... again the fact that they are on Italki doesn't mean they're here to be language partners. Third... you have no history. You only got here yesterday. You haven't taken any lessons, you haven't corrected any notebooks, you haven't given any answers. You only have to look in the Discussions forum (which is where this post actually belongs; Notebook is for where you want to write something that you're seeking language corrections on) you will see that a lot of members are over other members sending them "Hi" messages. Without the sender having a history showing that they are serious about language learning they have no way of knowing whether the person sending them the message is genuine or not. If you are expecting to suddenly pick up a raft of new friends as soon as you sign up... I think you're bound to be disappointed.

Hang in there...cheers!

Maybe you need to wait for a day or two?