No response or updates

I've been trying to track down a letter being sent from China to Durban through Ems for the past few days. The tracking stopped 4 days ago when it said it was sent to Johannesburg. Now I can't find anything. Ems South Africa can't help me and don't respond to emails. Ems in China doesn't have email. How am I suppose to find out where this letter is? It's extremely urgent and important!