telkom account

hi last year they steel the landline cables ,and Telkom tell me they are not gonna put new cables in were im staying so I went to Telkom to cancel the account and they say I must do it online (I don't have internet no cable) so I went to spring mall and a lady help me do it , but now they send me every month a letter to pay the full amount for line rental (but I don't have a line) please what can I do thank you