Did I wrong my relative to whom I was married and who then failed to provide for me and to complete the marriage, and then divorced me over the phone after a year and six months without consummation?

What you mentioned does not entail your having wronged him. Rather, he is the one who wronged you if he falsely and slanderously accused you, according to the words of Allah Almighty: "And those who harm believing men and believing women for [something] other than what they have earned have certainly borne a slander and a manifest sin." Likewise, he wrongs you if he does not pay you half of the dowry due to a woman divorced before consummation. You can refer the matter to the Sharia judge. As for maintenance, a woman is not entitled to it merely by virtue of the marriage contract, but rather by enabling the husband to consummate the marriage. Do not grieve over his leaving you, for perhaps Allah has averted evil from you, as Allah Almighty says: "But perhaps you hate a thing and it is good for you; and perhaps you love a thing and it is bad for you. And Allah Knows, while you know not." Allah may replace him with someone better. So supplicate to Him and strive in seeking a husband.