I moved into my current flat in 2016 and was advised by my management company to pay all my bills through One Utility Bill which I did - basically you pay them a set amount every month and they pay your water gas and electric direct to the suppliers.
I provided them with regular meter readings but they were rubbish (made numerous mistakes, charged random amounts, non existent customer service) and in October 2019 they claimed they needed to increase my payment by £40 a month due to excessive water consumption as there was a leak in my property. My management company investigated and this was simply not true, so at that point I terminated my contract with them.
They have now sent me a closing bill of £654, backed up by a statement issued by them. I have asked them for statements from the energy companies to prove this but they are unable to provide them. They are saying I now need to set up a payment plan with them or they will pass on my details to a debt collection agency and I'll get a CCJ.
I have looked at their reviews on google and this seems to be their standards practice. I don't believe I owe this money so how can I contest this? As they are not an energy provider they are not regulated by the Ombudsman. I would pay if it was genuine but I really don't think it is!