Removal fiscal reprentative on Financas

Hi.
I have a Portuguese passport and id with all my number onbthe back of the cards. I am from south Africa and found work here
I have been to financas 4 times to open an activity. But the say i need a representative because i dont live in portugal
How do i remove that representative as they no longer want to be my representatives.

Secondly i still need a representative in order to abrir actividad.
Must it be an accountant.

Any advise help will be appreciated

Thank you
Valentina