We have been informed that Paypal will have scheduled maintenance on their systems on April 17th from 05:00 - 11:00 GMT. During that time you might encounter problems while paying for Skype credit with Paypal.
We will update this post once the maintenance is completed.

UPDATE: Unfortunately we encountered some technical issues during maintenance and PayPal orders were delivered with delays during the entire day yesterday. We apologize for the inconvenience this has caused.