If some scumbag starts communicating by text or anywhere on the web, inform him once in clear terms in a return message or web posting that you have no interest in him. Make sure to keep copies of each communication, both from him or to him, in a separate file. If the contacts don’t stop within a few days, bring it to the attention of the university authorities and to the police. If you don’t get satisfaction there, bring it to the attention of a local female reporter-newspaper, radio or TV. They always are looking to fill white space or air time.