UNPROFESSION / BAD SERVICE

I signed for a FIBRE promo deal of R399.00 per for 12 months but for the past three months I have been paying R449.00.. Telkom cannot explain tome why I am billed this amount .This is wrong ,bad service from consultants who appears not to know what they are doing . Every I make a call to Telkom I have to repeat myself and explain the whole story . This is unprofessional .