Get the right phone number

Most telephone companies, including mobiles, give "free call" offers. Normally they don't include 0844, 0845 etc. The best way around that is to find a landline number with the old dial code. Failing that, look for an International contact number and dial it in full. This has saved me a lot of money and time as you very often don't have to wait in the same queue as evryone else.