Curves Midrand not responding to Cancellation of Membership

I called Curves Midrand on the 5th of April 2018 to cancel my gym membership and they said I must send a cancellation email to ********** I've been calling them and the one day they say their network was down and will revert back to me, the other day they said they will check the email and come back to me. They have not actioned my request. I'm don't know why they are not coming back to me