Non-Payers Advice Ebay

[animal]

Hi guys,
Ive just started selling some of higher end stuff on ebay.
To my dismay ive sold 3 cards to 2 buyers both of which are mentioned on this forum as non-payers pretty heavily in 2 separate threads(one has changed his username).
Ive only sold these items today, so I want some advice on the best steps to take early which may help my case later on should they decide not to pay or take too long.
Any advice from anyone who has dealt with this before would be much appreciated!
Thanks Guys

 

[luck_of_the_irish]

If you only sold them today who said they wont pay?

 

[animal]

Because they have a pretty coloured history of doing so.
I'm want to set up for the worst case scenario but hope for the best case. 1 of these buyers has a whole 5 page thread about him and his previous usernames

 

[luck_of_the_irish]

Well if they dont open a unpaid case in 4 days or whatever it is on ebay then block them