How to submit a form from C #

I am developing an internal application in C # that calls one of the banking sites. I need to enter a value in DDL, quantity in a textbox and neeed to find out the exchange rate.

here is the link i need to use.

https://www.timesofmoney.com/remittance/secure/rmtExchRateCalculator.jsp?tab=US&sendercountry=US&sendercurrency=USD&uiId=TOML&partnerId=TOML I used myWebClient.UploadValues ​​(C #) but the site is returning some errors can anyone help me with this.

My code:

    string uriString= "https://www.timesofmoney.com/remittance/secure/rmtExchRateCalculator.jsp?tab=US&sendercountry=US&sendercurrency=USD&uiId=TOML&partnerId=TOML";

    // Create a new WebClient instance.
    WebClient myWebClient = new WebClient();

    // Create a new NameValueCollection instance to hold some custom parameters to be posted to the URL.
    NameValueCollection myNameValueCollection = new NameValueCollection();



    // Add necessary parameter/value pairs to the name/value container.
    myNameValueCollection.Add("selCountry", "United States");
    myNameValueCollection.Add("rmtAmount", "100");

    byte[] responseArray = myWebClient.UploadValues(uriString, myNameValueCollection);

    Response.Write(Encoding.ASCII.GetString(responseArray));

      

        
        
        
      

    

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