Why do I need to be £ 330 in credit when I leave?

Why do I need to be £ 330 in credit when I leave. Also why has my monthly payment doubled. I was never this much or anywhere near with my old company. I know for a fact costs have not doubled. I am pleased there is not a charge for an early exit.

Where does it say you have to be £330 in credit when you leave?

And there’s no such thing as an “early exit” when there’s no minimum term.