Paid for a Booster session with my friend in April

Paid for a Booster session with my friend in April 2015 and since then I have not got any session booked with the personal trainer as when I complaint at the gym, a lady by the name of Chrize sent a whatsapp on May 26 to ask me about my availability and I gave her my schedule and she said she was fully booked for the month and will let me know as soon as she is available. Its July now and still waiting for her. I want my money back as this session is failing to take place. Its over three months now of waiting for a personal trainer. I am no longer interested in this booster thing, my friend got only one session with Chrize in June and that's was it. Yet when we took this out we were promised that we will get session the following week.