How can a 24 month cellphone contract price be increased after 12 months?

When is a 24-month cellphone contract not a contract? When it's with MTN - who has the "right" to increase my contract price by 5% after one year. To get to speak to a consultant is impossible, so the subscriber must just "suck it up"???? So why have a frigging contract? This will rake in billions for the network at the expense of hard-pressed retired persons like myself. DISGUSTING