Planet Fitness is running a **** with memberships

When I signed up in August, I was told that I could qualify for an 80% discount on my gym membership if I sign up for a Sanlam Reality benefits programme. I did exactly that, and sent confirmation to the individual that handled my membership process. Fast forward to month-end, I've been debited the full amount. Nobody from the Fourways (The Buzz) branch wants to assist me. I emailed with my complaint and I had to send a follow up email due to non-response. The manager at the branch tried to call, instead of responding to my email, and when I requested that they email, so I can keep a paper trail of the conversation, they then said I should contact the individual that handled my membership process.

What type of customer service is this? Is Planet Fitness running a ****? I'd like some assistance in resolving this because I signed a contract under false pretences.