$request = '<?xml version="1.0" encoding="UTF-8"?>
<lastMod>2018-01-01 00:00:00</lastMod>
curl_setopt($ch, CURLOPT_URL, 'https://app.webshippy.com/wspyapi/GetProduct/xml/');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(['request' => $request]));
$result = curl_exec($ch);