I have removed a couple of variables and only created one checkbox groupname.
This seems to work better, however i can only select "1" checkbox at the time.
How to setup multiple checkboxes with querybuilder?
$filterData = new WA_MySQLi_RS("filterData",$datasheet,0);
$filterData->setQuery("SELECT tablename.* FROM tablename WHERE tablename.country = ? AND tablename.company = ? ORDER BY tablename.company ASC");
$filterData->bindParam("s", "".(isset($_POST['searchInput'])?$_POST['searchInput']:"") ."", "-1"); //WAQB_Param1
$filterData->bindParam("s", "".(isset($_POST['filter1'])?$_POST['filter1']:"") ."", "-1"); //WAQB_Param2
$filterData->execute();