If your supplier has gone into administration it’s important not to panic! Your supply will not be cut off and any credit you have accumulated will be passed on, and your new supplier will be in touch very shortly explaining your new tariff and the next stage, but your credit will likely take a few weeks to cross over. Importantly, if you are in debt and your provider has stopped trading, you will still owe that and it is important you pay it to its administrators or the supplier that takes over its business.
Citizens Advice recommends taking a note of your meter reading and ideally a photo too, downloading any bills available in your online accounts.
At Eureka Property we recommend waiting until you have your new provider before searching for a better deal because you won’t be charged an exit fee if you move.