In my first playthrough I got invaded sporadically, but once I got to the darkmoon forest and joined the covenant I had a lot of luck using the ring and doing invasions there. I was level 40-50 at the time.
However, once I got a little further the invasions and effectiveness of the cat covenant ring waned drastically. At level 70 I couldn't get many pvp matches at all, and I tried all of the different pvp covenants in different locations (mostly the forest). The red summon sign didnt seem to do anything either. Last but not least I've never even seen a red ring in the pvp arena, let alone gotten a match going.
The only time I consistently got invasions again was in oolacile right after killing Artorias. However, once I killed the boss it didnt seem to work very well anymore.
Can anyone help me out? Im level 95 in NG+ at this point and I really want to do more pvp. I've read a lot of people get to lvl 125 or something to do pvp but I feel like it should be working more than it is. Am I missing something?