Unknown debt

So I went to go check the gym facilities and then they gave me a contract that I did not fully complete, I haven't even trained at Body Lab Pretoria Arcadia and they called me three month after my visit telling me I owe them 3000 rand.

My complaint is that the memebership was 150 but in 3 months they told me I owe that much due to the calls they tried making and emails they sent. I am so disappointed at this company as to how they charge.