Two things I learned about email:
1. In a long email chain (the bottom of email) , if an important email is inadvertently or deliberately dropped, then add it back. If you want, just quote it — “as I said in the email of blah blah…. (see below)…”
2. Know who reads email, who doesn’t, and who deliberately ignores what is inconvenient. This is important. Widen the cc list.