Breach of contract

Please can someone assist in a proper explanation. 2 years ago, i signed a 24 month 20Gb top-up data package at a reduced "special price" of R599 per month. 11th of March 2019 will be the end of this contract. I have 2 issues.. 1. As of the 1st of Feb, my special price is no longer valid and i am told i need to pay R999. Why?! This is not what i agreed when i signed for 24 months! Now after 22 months, the price nearly doubles!! 2: I call to cancel my contract with 30 days notice and now get told my contract will expire at the end of March not the 11th as per my agreement. I have given the required 30 days notice. I dont mind paying pro-rata for March but i refuse to pay full month when i have given 30 days notice again as per the contract. Pls can someone who knows whats going on contact me to sort this out. YOU VODACOM are in breach of contract!!! I have upheld every bit of my end!