not able to save form function in excel file i received

i received an important excel sheet with from functions after i edited it libre was showing all the form function in it I saved and sent the file there all the form function were absent from file in all the sheets. when i opened the file to check my self they were absent , i created new file apparently it shows the functions while creating but after i have saved the file all functions disappear. I am new to libre please help . i need this file, very important project for me.