Had the same problem. Then I realised the giant in the church still called me "stranger" or "rogue" instead of spear despite me having the ornament equipped. Then I went to the shrine and gave one spear token, the one you will find beyound the ladder that leads to Midir. After that the giant called me suddenly "spear". And EXACTLY one second later I was summoned! But even as a spear you will sometimes just not be summoned. My guess is it's a bug that will place you always at the end of the line when it comes to "who is boss next" for whatever reason. Change your covenant for a second or leave the area could help in such cases. Or, if still nothing happens, restart the game. What could possible also be a problem is your Soul Level. Try to stay around SL120-140. Thats where most people stop leveling up.