Telkom Makes you pay for a service they cant provide

i signed a 2 year contract with Telkom for home internet on 29 may. they told me that i would have internet in 3 weeks(instillation period) i have waited the 3 weeks and nothing happend. i went to reds mall where i signed the contract and they told me that they can do nothing about it. i have sent mails to telkom i have asked them to contact me and still nothing. On the first of July the debit order went of so now i have paid for a month of internet that i don't have. how can they make someone pay for a service that they didn't get?