Supersonic takes money, when I am already in credit.

If I could give a zero I would. This is the 2nd month that they take money off my account because they cant fix their billing. The government was doing a VAT increase, so Supersonic decided to bill me twice just with the different VAT percentage, now they never reversed the 2nd invoice for May. Now it looks as if I am in arrears when I am not. When the money went off double in May, I wanted a refund, I was told they will keep it as a credit and I am covered for June. Guess what...they took money off my account again because they cannot sort themselves out and now I must pay for their incompetence. This is going to happen all the time. These people dont even respond to queries I load online, I have to phone them in order to get answers. How many people havent they ********** because of they dont want to reverse that 2nd invoice from May.