Utterly useless Telkom - Mobile upgrade

TELKOM is just as ******* as the government, went to upgrade, upgrade were done, the salesperson told me I would only be billed for the new contract, HOWEVER when the bill arrived they charged me the first month for the old device and the second month twice for the new device, I spoke to one of their very helpful and actually utterly useless help desk people, who told me sorry go and sort it out with the sales person. I emailed them twice and received that useless we will contact you in 48 hours however that never happened. The debit order went off. I would like to cancel my contract as its my right as per the consumer law, We pay for a service and like the government they steel our money and don't deliver