Sell Direct unreachable

I was contacted by a reseller which I though was Telkom Mobile (later found out the were Sell Direct) and they had all my contract details. I signed up after along while eventually recieved the package, the next day they phoned me to activate the sim, but after 4 days the sim is still not active. Their customer care line is useless and no one answers even after contacting Telkom. I have no way to contact Sell Direct and I'm stuck with a sim and device I cannot return as there is no way for me to get back to them if I cannot even get it activated. I am completely reliant on Telkom to assist me with this issue considering Sell Direct is operating on behalf of Telkom Mobile and had access to my contract information. I am not happy.