Telkom you did me wrong and you must know that am not happy

Am so disappointed with telkom I took a contract phone with them for 24 months to pay which was R299 per month but to my surprise am billed R319 for the past few months an when I call them today I was told they increased data price without my consent 😢 how can they do alterations on a fixed contract without engaging with me.....am totally disappointed an dissatisfied 🥲