Do not enter into a contract (or change a contract) over the phone. Demand seeing the written agreement, and being able to take your time. Be especially carefu

Do not enter into a contract (or change a contract) over the phone. Demand seeing the written agreement, and being able to take your time. Be especially careful if you initiated the contact yourself, as if you did, terms may be binding even without written consent. So make it clear you want to do it in writing. If you're duped over the phone, complain, first to the company, then (maybe in parallel) to the applicable authorities (the market regulator), as it is your right to do so. Your calls will have been recorded, so if you were duped it's probably in their interest to fold (and move to the next prey). If it all fails go to the ombudsman. It's all much harder if you don't speak the language, but all the more reason to ask for documents that you can get through Google Translate. Also, don't feel bad for being duped, and up sold on crap you don't need. It happens all the time.