Fix React Native IOS Issue

We have a react native mobile app which sends data to a 3rd party url. The result is verified by the 3rd party, and redirects to a payment gateway screen. Currently on android this process is working perfectly. Meanwhile on IOS, the result of the url and post data is leading to an error page. The script is very simple, and is using a webview to display the result. I will share with you a sample code, which includes the URL and a sample post data to send, and you need to show me that the result of running the fix you make will make the iOS version work properly like the android one, meaning it leads to the correct payment screen. Once you have successfully posted this data in a sample react native app on iOS, and then integrate the fix you make into our app. The problem with our setup according to the 3rd party managing the url, is that the user-agent is not being sent properly from our current iOS app, and hence it needs to be sent correctly matching to identify iOS. Please contact me to give you access to the sample code which includes the url and sample post data, and you need to show me proof that you successfully sent this data via post under a webview on react native iOS. No milestones before that. Once you do, i will be able to create a milestone and then integrate this code into our app. This should be very simple if you know your way around React Native and iOS.