Price increase unknowing

The price went up without informing me via email or sms as they claim they did. I have never received a contract and no agent informed me about the price increase as I have paid up for 6 months a head and after made 2 ekstra paymenst. I have sent numerous of emails regarding this matter explaining and informing evert time it's someone els calling again I explain my situation then they say they will get back and never come back to me. How can you sign up for something for a year and then prices just increase and you assume I got a mail or sms when I clearly did not it's unfair that a customer must be penalized when breaking contract but if the company selfs break it we as customers must be okay with it