expired acount

I was just called to tell me that my Acount is outstanding. I told them I don't have an Acount anymore. Now Vodacom says I still need to pay R700 they msged me on a data memory stick ??? How the hell must a read the msgs on a contract that isn't working. And that since last year November. Why didn't any one call me??? expect now that I owe money????? Since November??? Really