send him SMS "I love u too" so he will think that u have started a new relation, and his attention will be back to u.
after that u can decide based on his reaction: if he replied & seems to be wanting u again u can accept him, but if he didn't reply anything after sometime u can send him another SMS "Please ignore the previous msg sent by mistake to ur number" he will definitely respond.
Similarly there are many tricks to attract his attention in indirect ways.
good luck