it looks only string data gets missing, to resole this, Use 'IMEX=1' in connection string it helps you to read data in string format
Use this one when you want to treat all data in the file as text, overriding Excels column type "General" to guess what type of data is in the column.
Provider=Microsoft.ACE.OLEDB.12.0;Data Source=c:\myFolder\myExcel2007file.xlsx;
Extended Properties="Excel 12.0 Xml;HDR=YES;IMEX=1";
hope it helps