Does this only work for one-off messages? Or is it possible to send a message and then also get a message (or more than one) back?

we have 3 features on S4S. Send, receive and rent. You can send messages (3k sats/msg) and then you can receive sms activations (3k sats/code)

We're working on a feature where you can recall one of the numbers you used in the past to receive an additional sms.