Trending @Cognizant; Can ratings comments be edited?

There are some wrong comments updated by my new and current HCM. When I checked with him he pointed that my previous HCM gave the comments he just copy/paste. When I checked with the old HCM he said a typo and error and gave a different comment in email. What can I do with this email? If I raise GSD they are closing it as nothing can be done now. There must be an escalation process as I have it documented in email as proof