I was a bonehead and chose the wrong S o t for a suppressor transfer I have emailed them a 1/2. Dozen times with no reply. Tried to call during business hours only for their phones to say that they're not open.
They open at 9am central time. I’ve found if I call them at exactly 9am central, my wait isn’t long at all. Try calling any other time and it’s a nightmare. They’ll usually answer emails within a day or two as well.
Try their website live chat feature. You will probably have like 50-80 people ahead of you but just leave the tab open while you do other stuff and check in every so often. Type in all of the info needed and your questions and they will see it when your turn comes up.