Which version?
Which system?
Please describe step by step:
- how do you open/create the file?
- what kind of file is that? Which app created it?
- exactly how do you change the text?
- exactly how and where do you save the file?
- exactly what else do you do additionally to the file (if anything)?
- exactly which app do you use to check the result?
- in case you check the result in Illustrator: exactly how do you open the file?