gym company is a ****!!!

i went online and registered for gym and after a month i started getting double debits, i am not able to reach them on the phone and i no longer stay close to the gym branch. I have sent them multiple of emails with no response. I had login details and logged in to cancel the membership but they still charging me.. funny enough the details i was able to log in with before no longer work. This company is such a **** coz now they affecting my credit score and i have never used their services before ever!!!!