Calling me daily

I tried to cancel my membership cause I am not allowed going to gym due to my pregnancy - the doctor asked me not due to experiences I had in my first trimester - but I still pay my membership cause cancelling it is going to cost me more - but now i skipped one payment and have asked them to deduct it next month and guess what - Virgin Active has been calling me everyday - I have been explaining to them every time that I need them to deduct this next month - but they still call me and ask if they can deduct now, Ive explained to each agent the same story and they have said they will update and ensure that I am not called numerous times and still they continue to call me.