False advertising and breach of contract

You are *****... I receive this wonderful sms stating I can upgrade to premium for R599 per month. I called in and asked for how long will I be paying this. She put me on hold for quite some time and when she spoke again advised for a year but could be extended to 2 years. This morning I get a call to now upgrade me and now advised that this promo ends 31 March so I can upgrade for 1 month at that price. I agreed to the at least 1 year premium service at R599 pm and not for 1 month. I demand that what was agreed on in my call to you is honored. I asked for the call to be pulled and now I will only receive feedback within 48 hours? I want feedback today! Why would I want to upgrade for 1 month? Does mos not make sence? Get that call and provide feedback!