So every time there's an unexplained payment on the card without an invoice, it gets flagged as fraud and the card gets frozen.
I bet you get maybe two instances of this before people start remembering to submit invoices. Make them wait two hours to clear and reactivate the card every time this happens.
You're in Sri Lanka and your company card isn't working? Damn that sucks, let me look into why. Oh, it looks like there's an unexplained expense on the card that has been flagged for fraud and the card is not operable. Please submit an invoice for all company card expenses as soon as possible to avoid this in the future.