To get in contact with most companies, chances are you'll have to call an 0870 number. These numbers are pretty expensive and will wind your phone bill up.
There is also an iPhone App available for you to use.
If you are in a situation where you cannot access this website, most companies offer a number to call when calling from outside of the UK. There is nothing stopping you from calling these numbers as the person on the other end will do the exact same thing as someone on an 0870 number.
Call the premium rate number and ask them to call you back straight away. You can make up any excuse to why they need to call you back or you can you just be honest and say you don't want to pay the premium rate, most companies will be happy to do this.