Month later- no letter/payment?

So I'm an artist. A client is sending me money via snail mail (aptly named in this situation), because she cannot access her PayPal. I do not work before I recieve payment, so it's not like I'm getting stiffed. My client informed me on July 8 that she sent the money that day. I don't think she placed tracking on it, so I have no way to find out where it is. Should I just give up hope of it ever showing up, or is it possible that I'll still get it? She hasn't contacted me since then, though I know she's been active. I'm not entirely sure what to do, as this has never happened to me before.