its them again - *********** accs dept

so after we receive sms's for the last year telling us to pay R380 every month which we duly have included Dec year end when they *****ed up we now get an sms to say we must pay R448 this month - huh? so we enquire phone the accounts dept where the chap tries to explain and sends us a statement which does not detail how it is now R448 - so the package is R365 per month and access fee of R85 - we have made no change to our contract/package at all or changed/upgraded the decoder so please explain the increase we even send emails - all say the same - hallo you told us to pay R380 the last year via sms so how is it possible it is now R448 with us making no changes - please explain????