Will not answer numerous queries sent

We started receiving sms's from a company called MBD regarding an outstanding SABC account, despit not having received any notification of this from the SABC, and also not being connected to ANY TV Services (SABC or DSTV) The SABC answered our intial e-mail advising that even if you just have a TV without making use of any services, that you still have to pay the licence fee. Really? For what? The amount keeps growing every month and we keep asking them what this amount is made up of and who MBD is. We cannot be handed over to a 3rd party for collection of an account when we were never informed by the SABC of this. They just don't answer and we refuse to pay fees or interest to this 3rd party when we were never informed by the SABC of this.