no books received

hi my son registred with Unisa and was promised that the five modules study gudes/books will be delivered via courie, only three books/study guides whete received. When we sent an email no feedback,phoned Unisa they say they are out of stock the two study guides/books assingments are due on the 23 Feb 14 what must he do as he needed the books/ study guides to do them what now as if they are not submitted he losses marks for them.Why did i pay for service and now im told there is no stock they cant do anything im annoyed with this as we have to follow up daily and still get the same answer.