The owner of the trademark could be solicited by private companies for publications of the trademark at a high cost in unofficial registers.
These registers do not have any juridical value. We recommend you to ignore such misleading proposals.
We kindly invite you to take a look at some examples of this scams below:
• Samples of misleading invoices
• List of confusing letters received by trademark holders
• WIPO: Samples of misleading invoices
When in doubt, please send us a copy of the invoice you have received and we will verify.