Unauthorized service charge with no prior contact!

This month I noticed an extra charge of R300 noted as "directory enquiries". I have never before had this charge. I called Telkom and the consultant said I need to call Trudon. I have not been able to reach them after numerous attempts. I have left an online message but gather that they will not reply. I HAVE NOT RECEIVED AN SMS, A CALL BUT THERE IS AN UNAUTHORIZED CHARGE ON MY ACCOUNT?? Such ************, ********** "businesses" should not be allowed to trade and swift legal action taken against them! You are **********!