on their IVR" or "in their IVR"

[tufguy]

I called an insurance company and there were two options available on their IVR(interractive voice response) system.

What should be the correct preposition here. "on their IVR" or "in their IVR"?

 

[tedmc]

I called an insurance company and there were two options available on their IVR (space here)(interractive voice response) system.

What should be the correct preposition be here - "on their IVR" or "in their IVR"?

I prefer "on", though "in" is also okay.