charged for services which were never rendered, now my account has been handed over and am threatened with discontinued services on my cell phone if I don't make necessary arrangements.

Message: Morning, I took a contract of 5gigabyte for R179.99 p/m from vodacom with a wifi router on 15 June 2018.On 18 June 2018 I sent vodacom email stating the router is faulty and it was confirmed by a walk in vodacom store.Vodacom aftersales said they will cancell the contract since I notified them within 14 working days and the amount of R513.00 which has already been debited from account will be refunded after I have returned the router via courier company which they organized. The router was collected towards the end of June and I was told the process will be finalized within 7-14 working days.Today it's the 17th of September and I made many calls everyday every week and I get a different story saying my query has been attended.This is very frustrating since now am getting SMS from their accounts department stating that I should make arrangements to pay because my fone will be locked. Please help.