Data not Synched due full storage lost

Dears, We have been using kobo collect for long period and we appreciate the company effort in ensuring proper data managment. The field team are using the Kobo app to collect data and we have get an alarm of full storage almost before a month and since we don’t budget plan for this year we have cleaned the data from the system. However, the data collected from field reported as sent to the system but was not visible in our system. We have donloaded and checked the data but it is not part of it though it is showing in the app as synched. we have recieved this type of issue from multiple countries. Therefore, we would like your support on how to get the data which was synched but not seeing in our system.