Hi @CarolineAugustine , sorry to hear the data and survey has disappeared. It may still be saved under the universities organization, however it is very common that the universities will wipe storages regularly for the sake of storage or for security. I would check with your university arcgis online administrator first to see if it was lost in a purge but also to check if it had simply moved. If you are nearing the end of a term, this is one prominent possibility. Otherwise, I know over the past several months after the AWS (amazon web service) crashes both survey123 and hosted feature service disruptions have occurred on a sporadic and hard to catch basis. If there is also a way to check logs or histories that might be of benefit for your case. If all else, I would ask to open an official ESRI Tech Support ticket not only to check for internal organization specific errors but also to help your case since it is an assignment and you can present your case and perhaps find a way either to reload your data or prove it had been performed. Hope this helps, I know when I worked under such organizations in schooling or for classes everyone always goes over saving locally and ensuring work is prepared outside the set system resets so I am not sure why it would happen during a term before everything was due.
Kind regards & God bless,
Jansen Lyons - Records and GIS Section - Public Works - City of Rio Rancho, NM
