SAP adapter of webMethods B2B

My webMethods B2B server has 3 SAP listeners.
Each SAP server is located in Singapore and India.
Sometimes India listener breaks down.
As you know the enabling green button becomes yellow. If we clik the yellow button, it shows the following message.
" Networks broke down or your setting is wrong".
But after some time(1-2 hours or less), it revives of itself. That is, it becomes green.
I guess the reason is the unstable network with India.

Supposing while the listener is down the RFC is called, what happens? Does the RFC call fail and data are lost? How can we guaranteed the RFC call to SAP?