In MSWord Document, any edited letters turn to dingbats and cannot be edited on my Mac

The writer sends me Word docs (from a MAC platform). I am supposed to edit them on my MAC in MSWord. (faster than redesigning in InDesign) But if I type anything new, or try to correct any letter, the letter becomes a dingbat or webding. (it does the same on the writer's Mac) Can this problem be identified and solved?

Greatly appreciated, if so! Thank you.