Icloud 20 GB plan payment issues

I am trying to upgrade from the Icloud free plan to 20 gb.

The price for this upgrade Apple say its 0.99 EUR for Europe.

Firstly, I was not able to complete the purchase with my VISA Electron card (I think it's a debit card). The card was declined and I don't know why.

Secondly, when I have checked the transactions on my card account I discovered that Apple - Itunes Luxembourg - was trying to charge me actually 1.99 EUR instead of 0.99 EUR, but the transaction was blocked.

Could somebody explain me what is going on ? Why Apple do not recognize a perfectly valid card and why the amount was double compared to what they advertise?? I am still an Apple fan and I don't imagine they try to cheat us and overcharge our purchases.

Thanks in advance for clarifications,

Catalin