As I have completed almost 550 shops for SR, and although this advice was not solicited, just as with Maritz I absolutely recommend calling, as opposed to mailing. Their toll free number is 866 518 6508. On almost all of the occasions I have phoned them, a person has answered my call, but only between 09:00 and 17:00 EST on weekdays.
Of the 161 months since their beginning, I have received a check on 116 occasions, with all arriving approximately 50 days after the close of the month in which the work was accepted. MY personal rating of the MSC is a solid 10, BUT, those for whom a more rapid payment is either required or desired, may not agree.