Well, they've felt no sense of urgency in resolving the many, longstanding withdrawal issues they have from owner's of other coins.

If you send them the Lisk they will steal it.

Can we think of a way to reimburse the customers ripped-off by Bter without using Bter themselves?

It would be good for Lisk to be seen to try to help ripped-off users, it would be bad for Lisk to be seen enabling a scam by the crook Lin.