I Got Relieving In Mail It Is Valid ?

I got relieving in mail.Thur mail i joined another company now my ex employer asking for relieving letter and experience letter will give you after do pending work.
In relieving mail his mention only one line relieving form your rolls at this date.
1. can they deny me relieving and experience letter?
2. relieving in mail it is valid.

If the email is from the competent authority of the HR department that is valid. On that basis they cannot deny you experience letter. However, if some person not competent to relieve you without any formal order from the HR, that may not work.

Its small company where every thing handle by directors, that mail is form General manger (director).