How do I know if the seller actually released the sats?

If @lnp2pBot tells you that the vendor released, it really is, but if you want to verify it you can do it as follows:

Write to the bot /listorders and if the bot is still in the process of paying your invoice the status you will see will be PAID_HOLD_INVOICE, if the bot has already paid the invoice the order will not appear on the list.

When an order has status PAID_HOLD_INVOICE, the seller no longer has any responsibility because he/she has released the sats, if you have problems receiving go to the section The seller released but I don't get the sats in my wallet.