Bad service

I had a Virgin Active gym membership over a year ago, which has since been paid up. Whilst I was still a member I took a package for 3 personal training sessions which amounted to R330, I did not, however, receive those sessions as he person who was suppose to train me made contact with me way after I no longer needed the sessions, Now Virgin active has taken me to lawyers for personal training sessions that I did not receive and are demaning payment of this amount. VVM attorneys has been calling me demaning such payment. My contract ended and it was paid up and I did not renew it afterwards. Why should I pay for an "added extra"/services that were not rendered to me? This meant that I have been handed over for non payment Write off the amount as my inital 1 year gym contract has been paid in full.