I usually get paid by QAMS within about 10-15 days after I complete a shop. They are one of the fastest payers.
It sounds like a check was generated and mailed to you but is lost in the mail. Most places ask you to wait 4-6 weeks before generating a new check for a lost one because it involves putting a stop payment on the first check involving a fee.
Don't email them, CALL. And, by contact person, do you mean the scheduler? If so, instead try contacting Mary Furrie, 800-580-2500. She's very responsive.