Cave, that does sound like fraud.
It sounds like my mother five years ago, at a point when the dementia was just starting to kick in. I knew about it because I had started managing a property for my dad, so knew there were problems with admin, contract signing, payments, tax returns etc, but my brother did not see it. In retrospect there were also problems with maintaining her home, hoarding - she would buy the same things on each supermarket trip, forgetting she had cupboards full at home, and keeping the house clean, plus the start of repetition in her conversation, and a diminishing interest in others. As well as a ferocious reaction if you ever pulled her up on anything - it was always someone else's fault. (Usually mine, at least when she was speaking to my brother - he obviously believed her rather than me!)
The people who sold my mum TV and Sky box protection were clever and kept within the law. It was protection, not insurance, so not regulated, and there was a cooling off period. However it was three year contracts and regular payments, and half way through the first three years they would confirm a renewal for an extended three years at a far higher price, again with the statutory minimum cooling off period. It was clear that my mum's phone number and address had been sold on many times. Its a pity you did not get a new phone number with the new address.
Luckily my mum does not remember her new address so even if she has a SPAM phone call she can't tell them where she lives, and I am careful that she only has a savings account with a debit card, which does not allow standing orders or overdrafts, and which does not have a cheque book, so her spending is limited to what is in the account. (Which I control and which is set to an amount she could afford to lose, but which I can top up should the carer need to buy something.)
Having to take over against someone's wishes, in their own best interest is awful. My mum screamed at me for about four months about stealing her cheque book from her. Financial independence, and a fear of losing her money and being destitute in her old age, were very deep rooted. Eventually she forgot, but it was difficult. I had to be careful that she always had money in her pocket, otherwise she would complain to my brother, who was not on the same page as far as her disability was concerned. And if she had money in her pocket she hid it, could not find it, and then thought it had been stolen.