Improper experience letter

My company has been acquired by other company and after leaving my job they wrote in my experience certificate that you signed NDA and if you violate that then legal action will be taken against you. However NDA was signed already so no point to write these lines in it. When I asked then they said it's standard format. It mean you can write anything in it.Secondly, they haven't mentioned anything about new company who purchased the earlier company. I asked them please give me experience of new company as you have been acquired by new company then they said its a part of new company so not required and if any employer will verify then we will provide information. How come they are not giving me experience of new company even I said mention anything about new company that is fine but they didn't . Please tell me law in which we can take legal action or should I ask new company about this point and what??