Hi. I am wondering if anyone can help me with this small packet i'm supposed to receive a long ago.

The tracking no is RB472580861CN. I'm wondering why in this web site it said my tracking no doesn't exist, but in 183 website, the tracking no shows the item had been at its "final delivery" on july 11th. Anyway, I haven't received this order. Can anyone here help me figure out what is going on? The seller didn't respond to my messages.