Hi Lau86, i had a similar experience with T. Mobile Flex, 18 month contract £35 per month allowed me £185 per month as a combination of talk and text.
I only had the contract in force for three months and although paying the same £35 per month my monthly allowance suddenly dropped to £179 talk and text, so i rang customer services and this baboon who answered swore blind that i had been using wap services on my phone. I have never, nor would i ever use my phone to access the internet, unless it was an absolute life or death situation, stranded miles from civilisation, i may quickly in those sort of situations, but it would have to be an absolute emergency. I told this clown, why would i use the internet from my phone when i have a pc at home....but he just carried on with his excuses about their records showed internet uses. I'm afraid, probably wrongly in hindsight, although at my time of life i dont want any credit, i told said T. Mobile representative to shove their contract where monkey's put their nuts, took the sim out and snapped it up. Ive had threatening letters, but its not a priority debt, if they want to tell absolute lies, i feel in the economic climate at present, that i dont wish to talk for however minutes you get for £185.....oh and to surf the internet, sure T.Mobile, it if makes you happy issue a CCJ.....its not a priority debt, i would sooner concentrate on shopping around for some cheap bio-diesal for my car, chip pan oil etc., so now i have a PAYG Sim Card and i top it up £20 per month instead. I find 02 is quite adequate, and more courteous staff on their customer services.
I'm not saying you should take the probably reckless action i took, but my credit is poor anyway, so unless you are so bothered about getting credit, i think i'd consider plumping for a PAYG Sim..at least you can keep track of what you are spending each month. These lovely threatening letters have been coming each month now for around nine months, i'm afraid to say my shredder has them for meals....no action, all talk for the past nine months, its not a criminal offence to be in debt, apart from non-payment of council tax...keep a roof over your head thats your main priority, keep warm, and try not to get stressed it would appear that T.Mobile at least send plenty of threats but nothing more......just to re-assure you that you are not the only person to be scammed by mobile phone companies :-)