The 'mail' group
These nouns refer to ways of sending messages or information. Some of them, like telex and telegram, are no longer in widespread use. All these nouns except airmail, telex, and word of mouth are count nouns or singular nouns.
by airmail by courier by e-mail by fax by letter by mail by messenger by modem by phone by post by radio by satellite by telegram by telephone by telex by text by text message by video link by word of mouth
Most books can be renewed by using the Library Catalogue, by email, by text message or by post.
In all cases, owners of affected vehicles will be notified by mail.
He tried to contact her husband by phone but could not reach him.
Most have heard about the place by word of mouth.
Is it ever okay to dump someone by text? No.