Can't close my account and not for the lack of trying

Been trying to close my account since last year June. Everytime I pay off my account and call the cards division to cancel they say its done. Now this year I have been receiving daily calls to my work asking for a payment of R300. Have paid this amount and trying to confirm if the account is closed but I have been put on hold every time I've called and sometime phone put down on me. Disgusting customer service wrong email address given, no follow up.