If you buy a mobile phone handset and/or contract over the phone, online, or by mail order, you have some rights that you would not otherwise have if you had bought it from a shop. If you have an issue with the company that provides your mobile service, then you have the right to make a complaint to an independent ombudsman or arbitrator. This is a free service, and they could help to resolve any issues you may be having.
Buying a phone service contract remotely entitles you to be able to cancel the order and be refunded up to 7 working days after the order was placed, with no reason having to be given. However, if you ask for your service to begin immediately, then you are waiving this right.
If you have bought a handset without taking out a contract online, on the phone, or by mail order, you have seven working days from the moment your order is placed up until seven days after you receive the phone to cancel the order and demand a refund. However, if you damage the phone, its packaging, or initialise the phone, then you should understand that you are waiving this right.
Most cell phone handsets come with a manufacturers warranty, that you can claim on if the handset develops any kind of fault during the agreed period. If you damage the phone through your own actions, however, you will invalidate the warranty.
If your phone is not guaranteed, you still have the right to a repair, refund, or replacement if the phone develops a fault through no negligence or misuse on your part, depending of course on the age of the handset.
If you want to keep your old number when you switch to a new network, all you have to do is request a Porting Authorisation Code(PAC) number from your current service provider, give it to your new provider along with your old phone number, and the switchover should only take a day or two.
It might be worth your while finding out how easy it will be to get out of any contract before you sign it, as some contracts have long minimum terms and high cancellation fees.