Sorry but your post is lacking.
What I see from your post;
1] You submit the worksheets. Does that mean you open the workbook from a file on your hard drive to input the data then send the file elsewhere? If so, where is the backup copy? If you are the only one to hold the original file, who else has access to it to 'change the format'?
2] What do you mean by 'format was changed'?
3] And don't forget the other information, eg;
If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem.
I submit a daily financial report containing 2 worksheets. At the end of the day, the format was changed, the worksheet tabs were no longer there, and I couldn't get to the 2nd worksheet to file my report! I use Microsoft Excel 2003. Can anyone help???