MS Word stopped functioning as it has and now changed all of my formatted files

My MS office ( Word) cannot be updated because my Mac is too old. What worked two days ago is now formatting without my ability to modify. All of my archived word files are now altered to look like this: I f y o u a r e t r y i n g to c h a n g e t h e s p a c i n g s o t h u m a n s c a n r e a d t h e m, then you need upgrades that my OS cannot support. MS has screwed me. So Apple showed me their default program like Word ,called Pages. Every time I open a Word Document , I need to convert it to Pages. I certainly hope I don't lose my functionality with Excel. Or I am shit out of luck. I hate MS and will never leave Apple. I hope they don't leave me