hmm its possible they are cheating also, because DS 1 is full of cheaters afaik.. u can try to find the chameleon spell and hide somewhere. basically u transform into a set piece item like a barell and remain still until they move away..
That stuff is hilarious to pull off, more so if you back stab them..
Anyway, for PVP stuff, you want to focus, speed over damage.. if you are getting stunlocked, get high poise.. However, if your equip load is 50%, then you will do fast roll.. fast roll has a lot more invulnerability frames than slow roll, just google it out what I said above, you will find what you are looking for