Vodafone and other companies has the right to change contracts and prices as long as they give notice but what happens if you don't agree with the contract or the price rise???
If you are on a fixed contract then your stuffed or can you get out of the contract???

A very silly example but could happen, Vodafone puts a promotion out, $10 a month for home phone line and broadband, contract is for 12 months.  They get 10,000 customers to sign up, the very next month they put the monthly cost up to $50 a month and make changes in the contract.  

What rights does the customer have????