Theft or lack of customer service management...

I have had a Vodacom Simm only data contract for more than 15 years. Every couple of years I get a call from Vodacom that my account is about to expire, and I upgrade my contract for another 2 or 3 years. My current contract expired in Jan. I only found out my contract had expired when I realised that instead of around R400, I was being debited for ober R800 monthly. When I enquired, I was told that my contract had expired and that I was paying at a diffrent rate. There are new contracts available for less than R400. If I had been aware that my contract had expired, I would have upgraded with Vodacom. When I spoke to customer services, I was told that they had send a message to the contract number. The contract is for a Simm only data contract. I used the Simm in my router. I had not received any communication or my montly statements from Vodacom since the inception of my contract. All communication was send to my router. I have cancelled my contract immediately as I see this as theft. Theft to ***** an additional couple of months worth of premiums at a higher rate. I am going over to MTN. I will rather pay a bit more than be ****** by a greedy corporation. Either this is theft or **** poor customer service management. Either way I am done with being ******.