Whenever you face such situations, feel assured that someone has used Black Magic on you, as a result of which all your efforts become ineffective.
Though such prayog is not easy, but some Tantric expertise in it and torture innocent souls at the behest of selfish and greedy people. Such tantric have made Black Magic their profession, and use it on others indiscriminately at the behest of their adversaries, to mint money. Thus the happy life of the people is spoiled.
Such so-called Black-Magicians, no doubt can harm others, but they do not possess the powers to counter such Tantric moves. As a result the victim keeps on suffering and sometimes it leads to the death of the victim. It is in fact very easy to cause harm through Tantra, but very difficult to amend the damage done. In order to learn the art of saving, one has to undergo Sadhana and Siddhi, and only a Tantric of high calibre can do so.