Legal analysis: It is not illegal. If there is no authorization letter, only the voucher from the formal purchase channel (that is, the purchase invoice) is fine. The manufacturer has no corresponding legal support for any litigation claims.

Legal basis: Article 52 of the Trademark Law of the People's Republic of China can determine that the following types of behavior infringe the exclusive right to register a trademark:

1. Without the permission of the trademark registrant, use a trademark that is identical or similar to the registered trademark on the same or similar goods;

2. Selling goods that infringe the exclusive right of a registered trademark;

3. Counterfeiting or manufacturing other people’s registered trademarks without authorization or selling counterfeit or unauthorized registered trademarks;

4. Changing the registered trademark without the consent of the trademark registrant and selling the goods with the replaced trademark and put it on the market;

5. Using a mark that is identical or similar to another’s registered trademark as a trade name or product decoration on the same or similar goods, misleading the public;

6. Intentionally providing warehousing, transportation, mailing, concealment and other convenient conditions for infringement of the exclusive rights of registered trademarks of others.