MTN: 5% increase im contract tariffs during contract period

MTN has unilaterally informed clients that from 1 May 2022 contract subscription rates will be increased by 5%. This is in my opinion ********* because these are 2 - year contracts. So MTN buy in at lower rates than other networks but then increase the tariffs later on. This is unprofessional and misleading and unfair to clients as well as to other networks whose rates after the 5% increase are likely to be lower than MTN's for similar packages. The rates should remain the same for the full 2-year contract petiod. Only when new contracts are entered into should the increased rates be offered to prospective clients. My contracts were concluded telephonically and it was never mentioned that MTN could unilaterally increase rates during contract periods. I also did not get any contract stating that MTN could increase rates during the contract period. In my opinion, this is breach of contract on MTN's part.