Cancelled Contract

I cancelled my Vodacom Cellphone Contract (which expired last year) middle of January 2016 because we left the country beginning of February. I went into the shop and a lady did the cancellation for me. I also closed all my bank accounts. We left the country and I have been getting multiple phone calls a day from Vodacom (which I don't want to answer because it would be to my expense) at very inconvenient times because we now have a 8 hours time difference to SA, the one time I answered I heard it was in connection to an outstanding payment. I've been trying to contact Vodacom for a week now via email - which I cannot get through the security checks as well as on their online Chat, to which no one responds. I'm trying to contact you now through Hello Peter in hope someone will help me :: WOULD YOU PLEASE CANCEL MY CONTRACT WITH YOU (i still want to keep the number on pay as you go, I'll be visiting SA frequently) AND FINALISE ANY OUTSTANDING PAYMENTS FROM ME (which there shouldn't be as I cancelled my contract in Jan already) - I'm in the US and can only communicate online! SO PLEASE STOP CONTACTING MY MOBILE NUMBER!