EmailTemplateHandler on Case

Hello Everyone , 

I created a class to have email template depending of the case origin for my send email quick action, then I add that class to be use within the support settings, but it is not functioning, anyone have an idea why? Thanks in Advance

global class CaseEmailTemplateSelector implements Support.EmailTemplateSelector {
// Empty constructor
global CaseEmailTemplateSelector() {}
global ID getDefaultEmailTemplateId(ID caseId) {
    // Get the case record
    Case c = [SELECT Origin FROM Case WHERE Id = :caseId];
    // Select the appropriate email template based on case origin
    String templateDeveloperName;
    if (c.Origin == 'Billing DE') {
        templateDeveloperName = 'Template quick text';
    } else if (c.Origin == 'Support DE') {
        templateDeveloperName = 'Template quick text';
    } else if (c.Origin == 'Service DE') {
        templateDeveloperName = 'Template quick text';
    } else {
        // Default template for other origins
        templateDeveloperName = 'QT DE Signature';
    }
    // Query for the email template using the developer name
    EmailTemplate template = [SELECT Id FROM EmailTemplate WHERE DeveloperName = :templateDeveloperName LIMIT 1];
    // Return the ID of the selected email template
    return template.Id;
}
}