We don't have synonyms for telephone tax yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are telephone tag, telephone box and telephone sex.
(n) :
(idiomatic) A situation in which a person unsuccessfully attempts to contact another person by telephone and leaves a message instead, and in which the second person then unsuccessfully attempts to return the initial call and leaves a message for the first person, and so on as if the two are playing a game of tag in which the most recent person to have been left with a message is now designated as "it" (i.e. as the player now obliged to chase the other and to attempt anew to make contact).
(n) :
(idiomatic) A situation in which a person unsuccessfully attempts to contact another person by telephone and leaves a message instead, and in which the second person then unsuccessfully attempts to return the initial call and leaves a message for the first person, and so on as if the two are playing a game of tag in which the most recent person to have been left with a message is now designated as "it" (i.e. as the player now obliged to chase the other and to attempt anew to make contact).