Closure is overrated, but there are times when it is necessary. I don't believe in just not talking to someone anymore just because you decide it is over. I have had this happen to me before. I am an engineer and am by definition "clueless socially"
(j/k). Sometimes I express myself in a way that ticks people off. Sometimes the reaction from women was to break up and stop returning calls. I guess they assumed I would stalk them or something, but it would have been nice to at least find out what it was that pissed them off. It is so much worse not to know in those circumstances.
However there are situations where it is just best to move on. I think this is one of those situations. I had this manic depressive girlfriend that I took on a trip to New Orleans about 6 months prior to my moving there for work. While we were there, we went to dinner with some friends of mine that I used to work with. I think she basically told them that I was husband material, but she had her work cut out for her to "shape me up". That was the end for me. Her mood swings had just left me cold sometimes (although she could really be sweet). When we got home, I just stopped calling her. The next girl I met a couple of weeks later was the woman I have been married to for almost 13 years now.