COLLATE MSSQL/PHP/FORM

Question

I wanna to insert data to MSSQL by this:

$conn = sqlsrv_connect($serverName, $connectionInfo);
$tsql = "INSERT INTO table (name, name2) VALUES('$name_demo','$name2_demo')";  

My form looks like this:

<form action="index.php" method="POST" id="sky-form2" class="sky-form">

      <fieldset>
        <div class="row">
          <section class="col col-6">
            <label class="label">NAME</label>
            <label class="input"> <i class="icon-append icon-user"></i>
              <input type="text" name="name_demo" required id="name_demo">
            </label>
          </section>
            <section class="col col-6">
            <label class="label">NAME2</label>
            <label class="input"> <i class="icon-append icon-user"></i>
              <input type="text" name="name2_demo" required id="name2_demo">
            </label>
          </section>
        </div>

      </fieldset>
      <footer>
           <button type="submit" value="submit" class="button">SEND</button>

      </footer>

      <div class="message"> <i class="icon-ok"></i><BR>
        <p>SENT!</p>

      </div>
    </form>

Everything works fine except that some letters like ąćęó into the database looks like ąćęó

For example such word like: LONDĄĆĘ in the database looks like: LONDĄĆÄ

Any idea? I was trying to play with collate in the database - nothing helps.