The ring will not teleport you if you have been teleblocked. To use the ring, stand directly on top of or adjacent to the portal with the ring equipped and operate it.
If the ring is lost, it may be obtained by searching the rubble next to the quest's starting location, north of the church and museum in Varrock, on the safe side of the wilderness wall.
Also, speaking to the Strange Old Man at the entrance to the Barrows while wearing the ring allows for a few lines of dialogue regarding the ring.
If the ring doesn't show up in the rubble next to Summer, you may need to use a Ghostspeak amulet and talk to Summer before searching the rubble again.