Hi
wolaskow,
I can't help you with this question, since I can't check your personal information via the forum.
But when your contract is finished at the 4th of February, it's normal that you receive an invoice at the end of February and in March since the invoice contains the usage costs of the previous month. So for example: in March you received an invoice with the costs you made in February.
However, because I can't check the costs you made you have to contact our customer service so they can find out why you still get. When you're not in The Netherlands, the easiest way for you is to contact us via Facebook or Twitter.