It is important that the individual is indifferent you knew exactly what he deserved such a favor. To do this, try to gently and correctly explain why you do not want to communicate with him. Be honest and frank. If you do not find within themselves no desire to maintain a relationship, just report it, be sure to specify the reason. If you do not even want to start an unpleasant conversation, you can tell him of his decision in writing.
Sometimes people deliberately seek to generate interest and sympathy to the person using ostentatious disregard. As you know, there is nothing that stimulates to action to win as indifference. In special cases, even simulated hatred is effective. However, try not to beat and not get lost in their own provocations. It is better to start a new romance with positive emotions and beautiful courtship, and not to ignore.
In cases where you can not completely ignore the dialogue with the person to whom you have prepared for oblivion, for example, because of the need to work together to solve issues or training, to deter a negative manifestations. Interacting with you indifferent person in a common cause, try not to get mutual insults. You will need a lot of self-control and endurance to resist and not falling into the same situation.