Brick.ie The Irish Association for Adult Fans of LEGO®

Looking for some knowledge on two issues ive just encountered on BrickLink.

First is a NSS (non shipping seller) and second is a seller who has stopped replying to messages because i asked for a refund on a tracked order that has not arrived.

I opened a dispute with PayPal for both transactions.
I have not needed to do this before so im wondering how long this process usually takes and is there anything I should / should not do to speed up the process.

From what i can gather, the seller is notified I have opened a dispute so I have to wait for them to make the next move!?

There is an option to escalate the clames but at what point do I do this?