Urgently cancel my polices

I am your client through media markt in barcelona.
i have purchased several electrical appliances and scooters from the store, but quite a few have been replaced and now it is difficult for me to cancel. I have been writing them for several months asking someone to contact me and explain how to terminate these policies online, because the goods have been returned to the store and replaced with others, but on the phone i only get promises that an english -speaking colleague will call me - but no one does not return my call.
i am keeping all the emails asking them unanswered with solution. i wrote to them that if they don't describe to me in detail how to cancel the old policies or they don't do it themselves - the next step will be to contact a lawyer and the organization of consumers and users to seek my rights and get the money they are withdrawing from my account returned. Today, they charged me again, for installment for an old policy. Also, i have a renewal email for one of them! this is a lack of communication on their part with a customer who has been happy with the service so far, and now i'm thinking how to open a new account and close the one they're withdrawing money from!