Building dynamic Doctrine query

I'm trying to build filter for my database. Based on values of several form inputs I need to construct appropriate query. This is the code:

    $qb = $em->createQueryBuilder();
            $qb->select('c.title')
            ->from('Baza\BlogBundle\Entity\Conferences', 'c');         
    $conditions=array(
        $qb->expr()->gt('c.title',$enquiry->getNaziv()) );//First condition 

    if ($enquiry->getKontakt()!=null) {
         $conditions[] = $qb->expr()->lt('c.contactemail',$enquiry->getKontakt())}//Adding second, optional condition

    $conditions = call_user_func_array(array($qb, 'andX'), $conditions);
    $qb->where($conditions);
    $query = $qb->getQuery();

When I run this I get folowing exception:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, class 'Doctrine\ORM\QueryBuilder' does not have a method 'andX'

*EDIT After call_user_func_array() modification I get following error:

QueryException: SELECT c.title FROM Baza\BlogBundle\Entity\Conferences c WHERE c.title > ITRO AND c.contactemail < somemail@yahoo.com

Obviously, query is not formatted quite right. I was following this post:Doctrine DQL conditional query

Any thoughts?

I built dynamic query with the following code:

$em = $this->getDoctrine()->getEntityManager();

            $naziv = $enquiry->getNaziv();
            $drzava=$enquiry->getDrzava();
            $oblast=$enquiry->getOblast();
            $grad=$enquiry->getGrad();
            $provincija=$enquiry->getProvincija();
            $kontakt=$enquiry->getKontakt();
            $sajt=$enquiry->getSajt();

            $testquery = "SELECT c.title FROM Baza\BlogBundle\Entity\Conferences c JOIN c.topicid t JOIN c.locationid l JOIN l.stateid s WHERE c.lh = :lh";
            $testparam ['lh'] = $lh;

            if ($kontakt != '') {
                    $testquery .= " and c.contactemail = :kontakt";
                    $testparam['kontakt'] = $kontakt;
            }
            if ($drzava != '') {
                    $testquery .= " and s.name = :drzava";
                    $testparam['drzava'] = $drzava;
            }

            if ($provincija != '') {
                    $testquery .= " and l.province = :provincija";
                    $testparam['provincija'] = $provincija;
            }

             if ($grad != '') {
                    $testquery .= " and l.city = :grad";
                    $testparam['grad'] = $grad;
            }

             if ($sajt != '') {
                    $testquery .= " and c.siteurl = :sajt";
                    $testparam['sajt'] = $sajt;
            }

             if ($oblast != '') {
                    $testquery .= " and t.name = :oblast";
                    $testparam['oblast'] = $oblast;
            }

            $query = $em->createQuery($testquery)->setParameters($testparam);
            $result = $query->getResult();