Like CRA, all maintenance enforcement agencies have fax numbers or "rat lines" that you can send information to (if you have a file with FRO, if not then it is pointless). Be sure to put your file number on the top of every page that you fax in. Have a brief covering letter, outlining why and what you are submitting. The more information you provide the better but be sure it can be corroborated or you are wasting someone's valuable time... crying "wolf" this time (without solid information) may come back to bite you in the ass in the future.