Below is my reasoning, I don't think it's going to make much of a difference but I'm going to do it anyway because I can.
Even if I cancel my DD I'll still be able to pay monthly for the energy I use, I'm not considering not paying at all. It just means that my energy company can't bank on the £400-odd credit I currently have, which is increasing monthly because I'm paying more by DD due to their estimate of what I'll owe them in 12 months' time. Once that's been used up I'll pay them for what I use every month, when I've used it. There are a lot of people who won't be able to afford to pay for energy this winter and it's purely down to the Government letting Ofgem dispose of the energy price cap and give the energy companies the power to increase their prices every three months should they so desire, and oh boy do they desire it! The fact that these companies have posted record profits in the quarter since the April rise is just more evidence that the peasants are being screwed over once again to fill the pockets of shareholders and rich people who don't need to worry that they can't afford to run their fridge to keep their insulin cold. Imagine how hard it's going to be for people on a fixed income with card meters (the elderly, sick, vulnerable and disabled mainly). If you're poor or in rented accommodation the default option is often a card meter where energy costs considerably more than it would on a DD tariff, if you've no money left to topup your card you'd have no choice but to go without. Gas and electricity shouldn't be treated as a luxury, access to power, heat and light should be a basic human right in a first-world country.
If the Conservative Government really cared about the people of the UK it would be a simple matter to veto the next proposed rise in October. Instead we've spent weeks listening to leadership candidates' daft ideas of how many quids they'll give us/which taxes they will lower for us to help out like they're doing us a favour and we should be grateful. These companies aren't going to go bust because even at the rates they're charging now they're raking in profit hand over fist. My tinfoil-hat-wearing side wonders how many high-up in our Government are shareholders in these companies. They blame Russia vs Ukraine war for the prices but that's just a downright lie perpetuated by the MSM, nowhere else on the planet have prices increased to such a degree as ours have.
Something must be done and, from my personal point of view, I'd rather start with cancelling a direct debit which, lets face it is just an annoyance to them, in the hope that it will make them do the right thing, and at the very least stop the October rise, than go straight in with civil unrest. This Government threw the sick, poor and elderly under the bus during Covid and they got away with it whilst filling their own pockets with taxpayers' money for dodgy PP equipment deals, let's not let them get away with it again because more poor people will die.