Vodafone — Harassment calls for bill recovery which is not pending from my end

I had a Idea no -[protected] . Its not in use more than a year & a half. I had paid the bill last in May & requested the customer care to close the no . as its not is use . Now after few months they have again generated the bill & are asking me to pay & everyday its a harassment that I get payments calls from Customer care & I am tired of explaining them . The language is rude & they are forcing me to pay when I have not been using & I have already paid bills & requested to close the no . They are asking me for email etc which I dont have as I didnt know I need a email from them that the no is closed . I had just requested the recovery guy after paying my bill last which was allready a payment even though I was not using my no . That Time I thought I should pay off to close the no & hence did it . Now again I am not going to pay any penny & everyday these recovery calls are very harasssing . Its disturbing the mental health & Sanity for no reason .