Incorrect Contract Upgrade

Service request S3-8113U-UTGKI, About 1,5 months ago I received a bill of about R1500 which I disputed because I normally paid R945 a month, therefore I had about R600 overdue, I phoned the customer care and they told me it was an upgrade I did, I told them I have never upgraded , I am still using an old phone. Since then my phone gets locked and I have to call the customer care and explain the same story and they unlock my phone, I am totally inconvenienced and my time is wasted because I cannot run daily business routines. I pay Vodacom on time every month but I get these automated calls for collection that waste my time, There is a service request no that Olwethu confirmed only today that it won't be sorted quickly unless I get an Affidavit from the police station, now that's more of my time wasted because I would have to drop my work. I am very disappointed with Vodacom because I have to explain my query all the time , I don't think my queries are noted on the system.