WhatsApp have been banning certain users and has also deleted their chat history. With these temporary bans, WhatsApp aims to gain users attention so that they stop using such unsanctioned apps.
People are advised to use the official version of the app however they still sometimes opt for the unofficial version of the app. In case of you are the one to be using the unofficial version then you need to immediately take action now.
WhatsApp's FAQ page their to help users regarding two of the most common unofficial versions of WhatsApp which includes WhatsApp and WhatsApp Plus. WhatsApp has mentioned that they do not support such third party apps concerning their security practices.