Email attachment shows as .txt file

Hi,

I'm not sure if i'm on the right forum but i'm just getting a hard time with sending my file.

I have a .xlsm file that's about 46mb that i have to send to a recipient, i understand that the file is too big so i sent it to a compressed (zip) folder.
It then showed the file as 2mb, I attached it to my email (MS Outlook 2010) and sent it.
My recepient was able to see the compressed folder attachment, but what's inside was a .txt file which is only 4kb.

I checked on the available space of both our outlook and we both have more than 100mb free space. What do you experts think about this?

u can try using 7zip compression