Green Star Energy

I have been billed incorrectly by I made complaint by email. Which have not replied to. I said I would pay the outstanding amount, so I paid 75 pounds last. The 69pounds, because it was the outstanding amount, now I told I owe 147 pounds, I have charged supplier, so I would think they cover the amount for this month. It initially showed that I owe £220, but only showed that owed 69 pounds, so I thought that I had paid it off completely. Can explain how this has happened. I moment I owe notting then 147 pounds.