Bulb will unilaterally greatly increase the direct-debit if there is just the slightest deficit in an account towards the end of winter, even if an account is well over £100 in credit at other times of the year. The supply companies should be required to get the customer's consent to increases in the direct-debit of say more than twice the rate of inflation! Since their debit-charging algorithm is highly in their favour, they are of course very content with it. With a deficit of less than a pound at the start of February, Bulb decided, via their algorithm, that I should be paying more than twice what I had been paying, every month of the year!