The double debited me while my contract was cancel

Good Day,I would like to log a complaint against Absa Gym,i was a staff member and resigned ,I cancelled my membership a month in advance as per the agreement of the month to month contract,even when they had to cancel my membership there were a lot of problems and run around,eventually it was cancelled,The last instalment bounced and then they instead of them debiting me for the last instalment on the following month they debited double,which I think then its gonna keep reoccurring because possibilities are they never cancelled my membership,I want them to refunf the 1 instalment and make sure I never get debited ever again,the service sucks because I called them and I was given an email address to send my enquiry to and I snet it twice but that person never came back to me,Email address is [Email Removed] my full names are Phephile Mthembu/Dlamini ID no is ***, my cell no is *** and ***