Please don't switch!

I wanted to support a local company and the tariff seemed good so I switched to isupply energy. t has been a truly awful experience. As others have said the customer service is terrible. My metre stopped working and it took dozens of emails, phone calls etc and 5 months for them to respond and then they charged me for the metre and estimated a ridiculous amount of electricity usage that they now expect me to pay above the correct amount that I was paying each month. It is almost impossible to get through on the phone but I don't object to needing to use online communication in return for a lower tariff. However, their online system has failed several times over the past few months. They claim they cannot read messages from me and their online system is very clumsy. They promised compensation for the appalling customer service but have never paid and deny it even though it is clearly written in an email from them. I have no idea how to get them to sort my account out. I have left them and closed my direct debit but they are still claiming I owe money. If anyone has any suggestions they would be gratefully received but please don't be tempted to switch to them!