I just found the phone. I didn't know that I had lost it, but at some point I became aware of a small voice repeating the same sequence over and over again, and a search of the talking mouse led to the phone that was lying under the couch, and from which a voice came that chimed the ominous mantra: "Your code has been accepted. You now have access to the site untill you break the connection". It had been singing this song for 40 minutes already, and who knows how long and how many times it had sung this before.
Who was it that said it is easier to raise boys than girls?
The perpetrator had already gone to bed. Needless to say I have given him the scare of his life and he is paying this phone bill out of his own pocket money. By the looks of it he will still be paying it off when he turns 21. I am also filing a complaint with the phone provider and with OPTA, because this seems to me a far too easy way for semi legal businesses to rob unsuspecting people of their money.