No answer for 10 days

I recently upgraded my Telkom wifi subscription through Selldirect. Since I received my package on 16/03/16 I have not been able to register my SIM via either their call centre or so-called head office. I either get no answer or get hung up on. This allows me no chance to make use of my cooling off period to cancel this contract because I don't want anything to do with Selldirect. Seems like a **** to me. So help me if a debit order goes off for this new contract.