[TYPO3-mvc] query contains exception

[Bas van der Togt]

Hello,

I have a problem with the contains method but don't know what i'm doing 
wrong.

When executing this query from my respository:
$query = $this->createQuery();
$query->getQuerySettings()->setRespectStoragePage(false);
$query->matching($query->contains('services', $service));
return $query->execute();

I get this exception: "Unsupported or non-existing property name 
"services" used in relation matching."

My TCA
...
'services' => array(
	'exclude' => 0,
	'label' => 
'LLL:EXT:gc/Resources/Private/Language/locallang_db.xlf:tx_gc_domain_model_testimonial.services',
	'config' => array(
		'type' => 'select',
		'items' => array(
		 
array('LLL:EXT:gc/Resources/Private/Language/locallang_db.xlf:tx_gc_domain_model_testimonial.services.1', 
'1'),
		 
array('LLL:EXT:gc/Resources/Private/Language/locallang_db.xlf:tx_gc_domain_model_testimonial.services.2', 
'2'),
		 
array('LLL:EXT:gc/Resources/Private/Language/locallang_db.xlf:tx_gc_domain_model_testimonial.services.3', 
'3'),
		 
array('LLL:EXT:gc/Resources/Private/Language/locallang_db.xlf:tx_gc_domain_model_testimonial.services.4', 
'4'),
		),
		'size' => 4,
		'minitems' => 1,
		'maxitems' => 4,
	)
),
...

My model
class Testimonial extends \TYPO3\CMS\Extbase\DomainObject\AbstractEntity {

	/**
	 * services
	 *
	 * @var \string
	 * @validate NotEmpty
	 */
	protected $services;

	/**
	 * name
	 *
	 * @var \string
	 * @validate NotEmpty
	 */
	protected $name;

	/**
	 * Returns the services
	 *
	 * @return \string $services
	 */
	public function getServices() {
		return $this->services;
	}

	/**
	 * Sets the services
	 *
	 * @param \string $services
	 * @return void
	 */
	public function setServices($services) {
		$this->services = $services;
	}
	...

Can anybody tell me what i'm doing wrong?

Kind regards,
Bas