Post Request in VB.NET doesn't work properly - json

Question

I want to execute this request with cookies that I have saved in file(cookies are good because i can execute other requests to page)
http://www.banggood.com/index.php?com=event&t=recordSignInShare&fb_id=197203087314503_251208398580638&code=
Yes, last parameter should be empty.
When I open it in browser it gives me json data (no matter how they look)
but when i try to do the same request on vb.net app it redirects me to another page.
Here is code from VB:
Dim postData As String = "com=event&t=recordSignInShare&fb_id=197203087314503_251208398580638&code="
Dim bytes() As Byte = ASCIIEncoding.UTF8.GetBytes(postData)
Dim postReq As HttpWebRequest = WebRequest.Create("http://www.banggood.com/index.php")
postReq.Method = "POST"
postReq.KeepAlive = True
postReq.CookieContainer = cookies
'postReq.ContentType = "application/x-www-form-urlencoded; charset=UTF-8"
postReq.Referer = "http://www.banggood.com/"
postReq.UserAgent = "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.87 Safari/537.36"
postReq.ContentLength = bytes.Length
Dim postStream As Stream = postReq.GetRequestStream()
postStream.Write(bytes, 0, bytes.Length)
postStream.Close()
Dim postResponse As HttpWebResponse
postResponse = postReq.GetResponse()
cookies.Add(postResponse.Cookies)
Dim reader As New StreamReader(postResponse.GetResponseStream())
Dim strSource As String = reader.ReadToEnd
Return strSource
And it returns me html code, not json data :(
This is how looks request from network monitor when i open it by browser
Request:
Accept:application/json, text/javascript, */*; q=0.01
Accept-Encoding:gzip, deflate, sdch
Accept-Language:pl-PL,pl;q=0.8,en-US;q=0.6,en;q=0.4
Connection:keep-alive
Host:www.banggood.com
Referer:http://www.banggood.com/2016midyear.html?utmid=796
User-Agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.84 Safari/537.36
X-Requested-With:XMLHttpRequest
Response:
Cache-Control:max-age=0, no-cache, no-store
Connection:keep-alive
Content-Length:94
Content-Type:text/html; charset=utf-8
I think that original(from code) request/response headers aren't important because I can execute it proper just by opening this link in browser.

Answer 1

Problem was, that i need get request :P
Thanks the_lotus

Answer 2

Dim urlphp As String = "" & dominio & "" & carpetanoti & "/demanda_alta.php"
Dim Conexion As HttpWebRequest = CType(WebRequest.Create(urlphp), HttpWebRequest)
Conexion.Method = "POST"
Conexion.ContentType = "application/x-www-form-urlencoded"
Dim POST_DATA As String = ("&cTitulo=" & "Te necesitamos!!" & "&cMensaje=" & "ALTA DEMANDA TENEMOS DOMICILIOS PARA TI" & "")
Dim byteArray() As Byte = Encoding.UTF8.GetBytes(POST_DATA)
Conexion.ContentLength = byteArray.Length
Dim FLUJO As Stream = Conexion.GetRequestStream()
FLUJO.Write(byteArray, 0, byteArray.Length)
FLUJO.Close()
Dim Response As HttpWebResponse = Conexion.GetResponse()
FLUJO = Response.GetResponseStream()
Dim LEER As New StreamReader(FLUJO)
Dim ServerResponse As String = LEER.ReadToEnd()
LEER.Close()
FLUJO.Close()
Response.Close()