Problem with SQL DB

I view a SQL server database through a MS Access ODBC. Agents input new customer information into the database via a bespoke application which was built along side the database, In some of the tables, records have been deleted/gone missing for no reason. Thay are not continually deleting (for example around 3 months ago I found 1130 cells in one of the tables had been cleared, that number is still the same) Does anyone know if this is likely to be a problem between tables on the database/my ODBC or the application that feeds into the database?