I purchased a contract phone to then and I asked them nicely that I don't want extra spending either data or voice minute etc but they keep doing it even after I have complained to them several times they still doing it

I purchased a contract phone to then and I asked them nicely that I don't want extra spending either data or voice minute etc but they keep doing it even after I have complained to them several times they still doing it. Invoice with extra charges that I can't afford.