The impact of social media marketing activities towards customer satisfaction mediated by social identification and perceived value: analysis of JF, a Multi-Level Marketing (MLM) business during COVID-19 pandemic period = Pengaruh aktivitas sosial media marketing terhadap kepuasan pelanggan dengan mediasi identifikasi sosial dan nilai yang dirasakan pelanggan: analisa terhadap JF, bisnis Multi-Level Marketing (MLM) pada periode pandemi COVID-19