retrieveRejectedServices = () => {
    const rejectedServices = {};

    const {
        _allCategoryNames,
        _allDefinedServices,
        _acceptedServices
    } = globalObj._state;

    for (const categoryName of _allCategoryNames) {
        rejectedServices[categoryName] = arrayDiff(
            _acceptedServices[categoryName],
            getKeys(_allDefinedServices[categoryName])
        );
    }

    return rejectedServices;
}
Calculate rejected services (all services - enabled services)
@returns {Object.<string, string[]>}