[blablablub]

As per your other answer, websocket connections are established just fine

"Now, whenever a new Webhook response comes ... it doesn't have information regarding which instance was used earlier for making the websocket connection, it may send request to one of the instance where the connection was not established and thus our backend is not able to process this request from this particular instance."

just include the internal ip of the websocket connection to the data you send to your billing operator and then forward the post request appropiately.