It is best when sending a letter to use the "custom reverse notification". Notice not much increase the cost. In this case, if the letter is sent, without notice, in the recipient's mailbox is just thrown notice that the Post office N waiting for his letter, and a request to come and get it.
If the email is sent with a return notice, it will be given personally to the recipient. You will be asked to sign the acknowledgment of receipt, and will send a notification to you.
When sending a letter, you will be awarded a check which will indicate the unique identification number of the postal item (domestic or international). Don't lose the receipt before the letter will reach the addressee. And it is better to inform the recipient of the letter. If the recipient is you, then ask him to send you the ID information. ID information is tracked at every stage of the forwarding letters: administration, shipping, sorting, delivery to the addressee, etc. Usually, the information is recorded either in real time or with a delay of several hours.

Unique identification number of the postage indicated on the letter (not parcel).
If a registered letter or a registered letter with return notification did not reach the addressee, you need to go to the website of the Russian post in the section "Postal services – mail Tracking" (http://xn----7sbza0acdlkaf3d.xn--p1ai/rp/servise/ru/home/postuslug/track...).
In the "Mail ID", enter the identification number listed on the check. The number should be entered without brackets and spaces.
If the search is successful, you will see the status
Click "Find".
If the search is successful, you will see the status of your shipment, its location.
Remember! If the shipment you're looking for is international, it may be delayed for inspection by customs. In this case, information about it is unavailable as long as the letter will not be forwarded to the Mail of Russia for their further delivery on the territory of Russia.
If you search through the site Mail of Russia did not produce results, write to the requisition.
A statement in the name of the head post offices may be filed either at the place of dispatch of the letter or at the place of its receipt. You should have the document proving the identity and the original or a copy of the receipt (receipt). Application forms are available in every post office of Russia. In addition, they can download, save and print on the website of the Russian post in the section "Handling users of the services of FGUP "Pochta Rossii" (http://xn----7sbza0acdlkaf3d.xn--p1ai/rp/servise/ru/home/postuslug/remov...).
In the statement necessarily specify the address of the sender and recipient, unique ID number, surname, name and patronymic of sender and recipient, attach a copy of the receipt. Complete the application, pass it to the Director of admissions or through the information Desk. Under each application form has a tear-off coupon. This coupon will attest to your application. After some time, you will be contacted at the contact numbers or send an information letter about the results of investigation of undelivered mail.
Write an email to one of the addresses listed on the website of the Russian post (http://xn----7sbza0acdlkaf3d.xn--p1ai/rp/contacts/ru/home). Please include the ID number, contact details and wait for the answer.