Verified senders API stopped working after I requested to increase my quote e-mail to 20 mb

After increased my quota e-mail to 20 mb, verified senders API permission stopped working. And it seems I need to pay in order to get that fixed, which I do not think it is fair, since it is a basic thing that is supposed to work alright, and it was before quota e-mail was increased. How can I get it working again? Tks.