I used to work for eDonkey doing support, many years ago. There was a fair number of people selling "eDonkey PRO", "eDonkey Premium" or similar, so the problem

I used to work for eDonkey doing support, many years ago. There was a fair number of people selling "eDonkey PRO", "eDonkey Premium" or similar, so the problem is familiar. They'd pay them, then email us with problems, and demand refunds if they were unhappy. One particularly memorable email was something along the lines of "Cease this chicanery at once! You must refund my monies...". I've worked chicanery into conversations ever since.