Now I’m beginning to see a picture. 
As I understand it, Lacuna Satelittes are meant to work as LoRa-gateway’s in space.
It is not feasable that these satellites relay/bounce/respond-to every message that is received.
Just like in a LoRaWAN network, gateway’s are mostly receiving, collecting messages that can be sent over a backbone to be processed.
A gateway cannot receive at the moment it sends a message, therefor the ratio of RX:TX is in the order of 100:1 or more, so the network can function as intended.
Shure the satellite’s SDR receiver can detect your doppler-shift and can respond with a opposite shift so your simple meshtastic-like device will receive that packet as if there is no (doppler) shift. This can only work if the satellite responds fast (seconds or maybe a minute ?) because it moves so the doppler-shift and the needed opposite shift change over time. Which is important when you use a a smaller BandWidth.
Logically Lacuna can only bounce certain packets that are approved by the backend.
Maybe that is the fee (5$/month) for that you are talking about ?
You say that for the moment, there is a lag from 9 to 90 minutes. So you cannot know if your packet was received and will be processed.
So right now a satellite-phone is better for a reliable connection. In the future things may change.