Planet Fitness in breach of contract

I would like to cut a long story short. I have a lifetime pay-as-you-go membership with Planet Fitness. I joined via Planet Platinum in Sandton very many years ago, when they 1st opened. I tried to go to the gym last year, to be told that my gym membership is now canceled. I am still alive and therefore, from my side, I see no reason why it has been canceled. I have emailed, visited Planet Platinum, visited the Planet Fitness in the Marc, I have spoken telephonically and am nowhere further. Planet Fitness is clearly in breach of their side of their contract. I am asking them to please sort it out, I don't actually want to know about their internal issues. We have a pay-as-you go contract for my lifetime. I am alive. Can you please just ensure that you uphold your side of our legally binding contract please. No further excuses, discussions, or sending me back to the Marc to go waste my time.