Credits management-wrong date

Hi,
I paid yesterday (02 May) 1600 credits for doman name, but in my Credits management-Credits available,is wrong date...
You have used 1600 credits since 03 Feb 2012.
Why February?

And 2nd question:
When Im check domain name was free, but after filling the form, I received a notice..."You must wait few days to check domain name".
Why I must wait if domain name is free, and how long will I wait?

Thanks.