Help with registering

Hallo,
I've registered with Congstar under the Prepaid Wie Ich Will option. It's take the 15 euros from my account but it's still just saying.

"Ihr Wechsel auf 300 Min. wird demnächst durchgeführt/Ihr Wechsel auf 300 SMS wird demnächst durchgeführt." and I can't phone or text anyone. I'm confused and because I don't speak German I'm not if there's something I'm missing.
I'd be grateful if someone can help,
Danke schon

Hello tomheaphy,

you are subsribed to the two options, but your balance is too low to pay them. The deposit will be added to your balance on the 5th of April.

Greetings,
Ben