PhoneBurner requires all imports to be in a CSV file format.
If you do not have Microsoft Excel, there are other options to convert your Excel file to a CSV.
One option is with Google Sheets:
1. Click on the Blank Spreadsheet box
2. Click File
3. Click Open
4. Click Upload
5. Click Select a file from your computer or drag and drop the file onto Drag a file here
6. Choose your file
7. Click File
8. Click Download as
9. Click Comma-separated values (.csv, current sheet)
If you use a spreadsheet in OpenOffice:
1. Click File
2. Click Save as
3. Click Text (.csv).
You can also use a online tool like ZamZar to convert your file.
Click here for some other free file converters that you can choose from.