"You don't have to worry."
Translation:Ustedes no tienen que preocuparse.
If you change it to "preocuparTE" then yes. Remember that if you use tienes (tú form) you have to use te and if you use tiene (Ud. form) you have to use se
It is either:
(Tú) No tienes que preocuparte
(Tú) No te tienes que preocupar.
Preocuparse is a reflexive verb so the reflexive pronoun (se) is used as part of the verb and needs to be conjugated as well (in this case, te).