2.6 Irregularities in the notification 

Where a document has reached the addressee, if the EPO is unable to prove that it has been duly notified, or if provisions relating to its notification have not been observed, it is deemed to have been notified on the date established by the EPO as the date of receipt. If the EPO is unable to prove the actual date of notification, a letter, for instance, sent by the addressee and indicating the date of receipt, is accepted as proof. If it is evident from a reply from the addressee that they have received the document, even though they do not mention the date of its notification, the date on which that reply was written is to be regarded as the date of notification.