we do not share your data with anyone and there are many ways to control the visibility and storage life of your data here.
but the internet is a public space and you should always assume your data could be compromised.
be smart with your password, use tor or a vpn, and use pgp for sensitive communications.
I had the exact same scenario:
Marked shipped on 4/3, but never shipped. He responded with a tracking number with a ship date of 4/24. That means it was only shipped after I messaged about it.→