ASSIGNMENT LOST

I courier my assignments down due to the post office being on strike. The courier costs me a fortune with each assignment, but I take precaution so that my assignments arrive at Intec safely. I sent my latest assignment via courier in July, it was received by Intec on 17/07. I phoned on 21/08 to follow up on the results as it should only take 30 days. The assignment received was not yet even handed over to a teacher for marking, and the other assignment has been misplaced!!! Please note the two assignments were in the SAME parcel, and was signed for by Intec. How can one assignment be lost and the other received??? What are the people receiving the assignments doing??? I am very unhappy about this because I have received over 80% for every other assignment so far, and I have taken great care and made alot of effort on each assignment, aside from the amount it costs me to complete each assignment due to purchasing of materials and sample boards, etc!!! I want this sorted out or I will request a refund and cancellation!!!! Unbelievable.