"sales person said that the only payments that they accept is direct debit (direct access to your account, and you pay frees if they screw up) or by creditcard."
The reason is very simple. Internet access is so cheap that there isn't anything left in the charge for debt collection. Chasing up people who don't pay on time is costly. It IS a free country in many respects, and ISPs are free to determine how their clients pay. If the clients don't like that, they they too are free - to go and set up an ISP where their clients can pay by cash or cheque.
