I think you should redesign the VPS Management Area, it doesn't look so good. Try to redesign in a way that it looks clean and user-friendly interface.
Although your scheme colour is dark, but you should try to make it lighter and brighter so that I can easily use the VPS management. You can use some colours like blue, white or green etc.
The invoice. I really I don't understand how to read the invoice. It is extremely confusing.
So, did you see vpscheap.net VPS management? Clean and user-friendly. I am not saying yours not clean, but everything separated hard to find. vpscheap.net can find easily.
It is fine if you feel it's OK, because many people have different opinions.