Contract amount not debit amount

I signed a gym membership contract just now in Jan 2026. The amount on the contract and the membership amount debited are 2 different amounts and when I went to inquire about this at your Vereeniging branch I got back an email that states it was a system error and the sales person was told to quote the clause “I acknowledge monthly payments may change as per terms and conditions of the membership” what changes in just 2 weeks of signing a contract and with no formal notice of monthly membership payment change? This is honestly nonsense, I must not be held liable for your incompetence. I literally just joined this gym a couple of weeks ago to relieve stress and guess what I get the stress from them.