article: It's the same for him. What they don't know is that this "service" costs them money, even though neither of them recalls subscribing to it. Only when Mrs Dementieva calls her mobile phone network MTS, Russia's largest mobile operator, does she find out that she is being charged for it: 42 roubles (80p; $1.30) a month. When she complains that she never bought the service, the customer service representative calmly replies that yes, she did. She is experiencing the same issues as phone users in many other countries. "Turns out that shortly after I had signed a contract with them, they sent me an SMS, informing me that I had this music added to my account and that it was free for the first month, but after that it was going to continue automatically with a monthly fee," Mrs Dementieva says. "And to stop it, I had to call them and cancel it. "But I only use my mobile for calls. It is not a smartphone, the screen is tiny and I am not tech-savvy, so I don't read or send SMS. "I guess I had received this text but I never read it. And I certainly did not know I was being charged for it." Two of Russia's other big telecom operators, Megafon and Beeline, have similar services. Such practices have enraged users, and Russian online forums are peppered with angry comments from customers claiming that the services they never chose to have are costing them dearly. One blogger, Roman, writes that he bought an MTS Sim card to use for web access only - and still got charged for phone ringtones. MTS declined to comment. In the UK, industry watchdog Phonepayplus states that users "must not be charged for premium rate services without their consent" - and evidence of consent is required. "Where consumers are accessing high-cost subscription services, we have a system of double opt-in to make certain that they understand the full cost of the service," says Patrick Guthrie, director of strategy and communications at PhonepayPlus. To avoid hidden charges, Mr Guthrie says people should always read the terms and conditions in any advert. "Once you've seen how a service works and what it will cost, then make up your mind about taking part," he says. "Be wary of 'free' offers or fabulous prizes. If something looks too good to be true, it probably will be. "If you're signed up to a subscription service on your mobile but want to quit, simply send the word STOP to the service number." The organisation says that teenagers are especially likely to click on a service that promises to be free, such as a trendy ringtone, but do not read terms and conditions - until their parents discover a hefty charge on the monthly bill. PhonepayPlus has even set up a website called PhoneBrain to educate young people about the potential pitfalls of owning a mobile. When people move from a normal mobile phone to a smartphone, many may not realise that there are a lot of extra hidden fees, says
summary: When Maria Dementieva, a 56-year-old doctor in Moscow, dials her husband's mobile phone number, she hears music instead of a normal ringtone.