If your Excel file has values in the column like follow:
But the value is supposed to be 123244452113.
It means the value has been truncated. To prevent this from happening, please revert back the file format to the CSV file. This is the original format and the values won't be truncated.
If you still insist on using XLS/XLSX format, then follow the steps below to fix the truncate issue;
1. Click on the cell
2. Click on Format->Cells from the top menu. You will notice that ‘Scientific’ formatting is turned on by default.
3. Click on Numbers in the selection area. And set the number of decimal places to 0