If it is indeed a brand new item and has not been used before, then provided the cassette was not at fault, and it has to be said it "is" in most cases, then it should be a guarantee repair. If the new cassette will not load and the camcorder remains in safeguard mode then it would strongly suggest that the mechanism is faulty in some way and which can be due to a number of reasons, especially if any leverage has been used to extract the tape, however unfortunately you cannot really do anything about this situation as it requires considerable dismantling to gain access to the mechanism. Out of curiosity, when you say it stays in safeguard mode, is it with the cassette holder closed or open? and is there any error codes shown?