Nasty nasty service from this provider

I have never gone to this gym, some people came to my work place and I wanted to sign up However had an issue with the link and eventually decided to let it go and do it some other time and the guy that was helping me was so persistent, he was texting and calling me on WhatsApp until I was just getting annoyed and no longer interested in the service and then after a month I am getting calls stating that I owe the gym Huge amounts and I have been telling the people calling that I have never used these services and I have chaats with this guys being persistent and calling me yet they never want to hear it and I refund to pay debt of over 6k for service I never indulged in and I feel this is very unfair and ******** and very unacceptable