Excel Spreadsheet when opened in Libreoffice loses format.

I open a spreadsheet that has formulas etc from and external source, when I open in Libraoffice I lost the month headings on the worksheets, the cells are locked so I can’t just go an add them in.

I am running Version: 5.1.0.3 of Libra Office.

Any ideas please as this is causing delays in my processing some assignments.