My credit institute just messages me per SMS about "suspicious transactions" and in this reason they blocked today the card.
It was not about my own pledge, but i used my card for 3 more friends to get a pledge, because they don't own a card by themself.
I was calling them today, told them, which transactions are valid and they just confirmed them and opened my card again.
Cool thing btw. because i can be sure, my credit institute is caring for my transactions