New billing month, cannot reduce extra usage?

[#1]

New billing month today, and after I went over last month, I cannot change how much extra money I spend on usage.  I try and change it and it says over £10 only.  I know that the new billing month is today, so do I have to wait for a couple of days before I can change it?

[#2]

you might need to wait until all the invoicing has been done and you have your billing emails.

[#3]

He there,
You should be able to change it today. How much are you trying to change it too?

[#4]

I was trying to change the extra usage from £10 to £0 and it works now.  Must have been that I was just to quick for the system to update :).

[#5]

Too quick for us
At least it's sorted now!