You will still have to pay your fee until the end of your contract. For example, if you have 6 months to go and you are currently paying £20 per month, you will carry on paying the £20 a month for the next 6 months. You can ask Vodafone to downgrade your tariff, so you have less minutes, texts etc, but you will still have to pay the remaining months at the new rate. Make sure you tell them 30 days before the contract ends that you wish to leave, as you need to give them 30 days notice. If you do not give this notice, your contract will simply run on month to month until you give them the 30 days notice.
The last option is to buy out your contract, which will cost you the full amount of the remaining value; payable in one go. Using the above example, you will pay 6 x £20 which is £180 all at once. There may be a small discount on this amount, but it would be very small. The amount would depend on how many months you have remaining and how much the monthly payment is. If you downgrade your tariff, you will be able to pay off the contract in full at the lower rate.
Whatever option you take, you will still be liable for the money until the end of the contract - you can't walk away and pay nothing. There won't be an end fee as such, to transfer your number to pay as you go.
