VESTA, API, PHP. No user is added - php

Question

I'm writing a script to add a new user to the hosting control panel "VESTA". I write according to the manual for api: http://vestacp.com/docs/api/ Errors when executing the code does not produce, but the user is not added to the VESTA. My code:
$vst_hostname = 'dfsdfl.csfdsdsgds.com';
$postvars = array(
$vst_username = 'zdeslogin',
$vst_password = 'zdesparol',
$vst_returncode = 'yes',
$vst_command = 'v-add-user',
$username = 'demo',
$password = 'password',
$email = 'demo#gmail.com',
$package = 'default',
$fist_name = 'Rust',
$last_name = 'Cohle'
);
$postdata = http_build_query($postvars);
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, 'https://' . $vst_hostname . ':8083/api/');
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $postdata);
$answer = curl_exec($curl);
// Check result
if($answer == 0) {
echo "User account has been successfuly created\n";
} else {
echo "Query returned error code: " .$answer. "\n";
}
After running the code, the following line is returned: User account has been successfuly created.

Answer 1

The Russian community helped. Here is the code:
<?php
// Server credentials
$vst_hostname = 'sadsad.sadsad.com';
$vst_username = 'zdeslogin';
$vst_password = 'zdesparol';
$vst_returncode = 'no';
$vst_command = 'v-add-user';
$username = 'demo3';
$password = 'd3m0p4ssw0rd';
$email = 'demo#gmail.com';
$package = 'default';
$fist_name = 'Rust';
$last_name = 'Cohle';
$postvars = array(
'user' => $vst_username,
'password' => $vst_password,
'returncode' => $vst_returncode,
'cmd' => $vst_command,
'arg1' => $username,
'arg2' => $password,
'arg3' => $email,
'arg4' => $package,
'arg5' => $fist_name,
'arg6' => $last_name
);
$postdata = http_build_query($postvars);
// Send POST query via cURL
$postdata = http_build_query($postvars);
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, 'https://' . $vst_hostname . ':8083/api/');
curl_setopt($curl, CURLOPT_RETURNTRANSFER,true);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $postdata);
$answer = curl_exec($curl);
// Check result
if($answer == 0) {
echo "User account has been successfuly created\n";
} else {
echo "Query returned error code: " .$answer. "\n";
}
?>