external pendrive is read only
Are you sure it's FAT32, and not NTFS? MacOS can read NTFS but not write to it natively.

If you can't write to a USB drive formatted as HFS+ (Mac's native format), then I would agree that your office had put some block in place. How to over-ride that may not be easy or possible, depending on how they have implemented and what level of access you have on the computer.