KAG,
DHL should have given you a taking number so just check and see where your boxes are...
As far as the strike there is no such a thing ongoing so again, check your traking number or maybe call the bookstore and see if they have sent it at all.
Reasons to strike?Google search does better than any book your might order and read:
DHL, Unite Scotland, Marks and Spencer, DHL Supply Chain, distribution centre, strike action, strike - Supply Chain Digital