diff --git a/htdocs/admin/dolistore/class/PSWebServiceLibrary.class.php b/htdocs/admin/dolistore/class/PSWebServiceLibrary.class.php
index abbb3bbc4ed..201191d1262 100644
--- a/htdocs/admin/dolistore/class/PSWebServiceLibrary.class.php
+++ b/htdocs/admin/dolistore/class/PSWebServiceLibrary.class.php
@@ -272,10 +272,10 @@ class PrestaShopWebservice
 		} else {
 			throw new PrestaShopWebserviceException('Bad parameters given');
 		}
-		$request = self::executeRequest($url, array(CURLOPT_CUSTOMREQUEST => 'POST', CURLOPT_POSTFIELDS => $xml));
+		$request = $this->executeRequest($url, array(CURLOPT_CUSTOMREQUEST => 'POST', CURLOPT_POSTFIELDS => $xml));
 
-		self::checkStatusCode($request['status_code']);
-		return self::parseXML($request['response']);
+		$this->checkStatusCode($request['status_code']);
+		return $this->parseXML($request['response']);
 	}
 
 	/**
@@ -332,9 +332,9 @@ class PrestaShopWebservice
 			throw new PrestaShopWebserviceException('Bad parameters given ');
 		}
 
-		$request = self::executeRequest($url, array(CURLOPT_CUSTOMREQUEST => 'GET'));
-		self::checkStatusCode($request['status_code']); // check the response validity
-		return self::parseXML($request['response']);
+		$request = $this->executeRequest($url, array(CURLOPT_CUSTOMREQUEST => 'GET'));
+		$this->checkStatusCode($request['status_code']); // check the response validity
+		return $this->parseXML($request['response']);
 	}
 
 	/**
@@ -366,8 +366,8 @@ class PrestaShopWebservice
 		} else {
 			throw new PrestaShopWebserviceException('Bad parameters given');
 		}
-		$request = self::executeRequest($url, array(CURLOPT_CUSTOMREQUEST => 'HEAD', CURLOPT_NOBODY => true));
-		self::checkStatusCode($request['status_code']); // check the response validity
+		$request = $this->executeRequest($url, array(CURLOPT_CUSTOMREQUEST => 'HEAD', CURLOPT_NOBODY => true));
+		$this->checkStatusCode($request['status_code']); // check the response validity
 		return $request['header'];
 	}
 	/**
@@ -400,9 +400,9 @@ class PrestaShopWebservice
 			throw new PrestaShopWebserviceException('Bad parameters given');
 		}
 
-		$request = self::executeRequest($url, array(CURLOPT_CUSTOMREQUEST => 'PUT', CURLOPT_POSTFIELDS => $xml));
-		self::checkStatusCode($request['status_code']); // check the response validity
-		return self::parseXML($request['response']);
+		$request = $this->executeRequest($url, array(CURLOPT_CUSTOMREQUEST => 'PUT', CURLOPT_POSTFIELDS => $xml));
+		$this->checkStatusCode($request['status_code']); // check the response validity
+		return $this->parseXML($request['response']);
 	}
 }