Special Assessment Fee

Just received two identical letters on Friday September 18, 2015. These letters are advising me that I have not payed Suitelife Vacations Club their Special Assessment Fee of $424 USD and this includes a $25 USD late fee. THIS IS THE FIRST TIME I HAVE BEEN NOTIFIED or HEARD OF SUCH A FEE! Attempted to enter their Web Site and was unsuccessful. Does anyone know what this fee is for? Looked up Company Reviews and found similar complaints. ALL MEMBERS NEED TO INVESTIGATE THIS MATTER, and post there findings.