The solution is

FREE RIDDLE BOOK AT LIBRARY.

To find it,

take the last letter before every punctuation mark.

I thought of this because of the unusual words "Fiji" and "plea", which were clearly significant -

"Fiji" might have been included because of the J, but "plea" was clearly included because of the final A, and then it becomes clear that "Fiji" was included because of the final I.

Also in the title of the email,

"deck stair" ~ "dexter", which means right - as in the right-hand end of a word or clause.

Apparently the email address and title were meant to be a hint towards

“A Pickle for the Knowing Ones; or Plain Truths in a Homespun Dress” by Lord Timothy Dexter (or "tin of the decks stair"), a book which includes no punctuation - therefore we should be looking for punctuation in the email. But I solved it without needing this :-)

The solution is

FREE RIDDLE BOOK AT LIBRARY.

To find it,

take the last letter before every punctuation mark.

I thought of this because of the unusual words "Fiji" and "plea", which were clearly significant -

"Fiji" might have been included because of the J, but "plea" was clearly included because of the final A, and then it becomes clear that "Fiji" was included because of the final I.

Also in the title of the email,

"deck stair" ~ "dexter", which means right - as in the right-hand end of a word or clause.

Apparently the email address and title were meant to be a hint towards

“A Pickle for the Knowing Ones; or Plain Truths in a Homespun Dress” by Lord Timothy Dexter (or "tin of the decks stair"), a book which includes no punctuation - therefore we should be looking for punctuation in the email. But I solved it without needing this :-)

The solution is

FREE RIDDLE BOOK AT LIBRARY.

To find it,

take the last letter before every punctuation mark.

I thought of this because of the unusual words "Fiji" and "plea", which were clearly significant -

"Fiji" might have been included because of the J, but "plea" was clearly included because of the final A, and then it becomes clear that "Fiji" was included because of the final I.

Also in the title of the email,

"deck stair" ~ "dexter", which means right - as in the right-hand end of a word or clause.

The solution is

FREE RIDDLE BOOK AT LIBRARY.

To find it,

take the last letter before every punctuation mark.

I thought of this because of the unusual words "Fiji" and "plea", which were clearly significant -

"Fiji" might have been included because of the J, but "plea" was clearly included because of the final A, and then it becomes clear that "Fiji" was included because of the final I.

Also in the title of the email,

"deck stair" ~ "dexter", which means right - as in the right-hand end of a word or clause.

Apparently the email address and title were meant to be a hint towards

“A Pickle for the Knowing Ones; or Plain Truths in a Homespun Dress” by Lord Timothy Dexter (or "tin of the decks stair"), a book which includes no punctuation - therefore we should be looking for punctuation in the email. But I solved it without needing this :-)