Beware of scams!
It's very unfortunate, but trademark owners are often targeted by sophisticated scammers who send official-looking letters requesting unnecessary payments. Some even use the branding of international authorities such as the EUIPO and WIPO. If you receive unsolicited communications about your trademarks, query them with your IP attorney to make sure you're not getting scammed. The EUIPO itself has a useful list of known scam companies, accessible on this link. Here is an example of a fraudulent letter: