Utility Warehouse

I’ve been sent bills on a monthly basis which are externotiate. My last bill was in excess of £600 per month. I can understand if the weather was really bad and reaching minus temperatures. We’ve had the heating on the same since autumn and we’ve been told that our preplan or package has changed without our consent, estimations based on historical data is in relation to last year usage. I strongly feel there has been a mistake on the readings and calculations as this is pretty ridiculous and I’m considering changing suppliers.