Mystery Caller wants his son, who has just started secondary school, to have a cheap phone that can be used for emergency contact whenever he is away from home. He also wants a decent contract for it. What deals can the networks offer?

Mystery Caller is heading off to university in September. He wants an affordable SIM contract and decent phone to match his tight student budget. What can each network offer him? Are there any good student deals out there?

Mystery Caller is planning to go travelling in Europe over the summer. He already has a phone but needs a SIM-card that won’t cost a fortune when used abroad. What deals do the networks offer for roaming?

Mystery Caller has always used phones made by HTC and is looking to get himself a new device. He wants it on a monthly deal for under £30 – what phones will the sales staff offer him and who can come up with the best deal?

Mystery Caller has seen adverts for the new LG flagship, the LG G4, and decided he wants one. Which operator knows the most about the device and can come up with the best deal?

Mystery Caller is bored of the traditional brands like Apple and Samsung and wants something less well known. What do the advisors think are “alternative” brands and can they sell them well?

Mystery Caller is fed up with charging his phone every night and wants a device with at least a two-day battery life. Can the sales staff set realistic expectations and find the right device?