You'd be lucky to get a sea freight route now that would have them customs cleared and ready for pick up in Durban by late July. It's possible, but tight, by the time you get quotes etc. Your profile says Boston, which is a port area, so I guess you could start but asking freight forwarding companies what the best options are.

Even better, contact a freight forwarder in Durban. It's always better took have the receiving end arranging pickup and clearance. Things go smoother that way. ( assuming your stuff is bigger than just a couple of bags)