If you had not previously had access to the list of supplies, then I think you are due a full refund (unless the shop can offer an alternative, like a loaner extension table or machine).
My machine is also recessed, but the table is just slightly lower - maybe 1/8" lower - than the machine bed. It's annoying when I am piecing because it sometimes causes the seam allowances to want to go the wrong way. I do my quilting on the longarm, so this has not been a problem with ruler work, but I wonder if you might have the same situation. The ruler base really does need to be exactly level with the machine bed.