Sorry to hear about the issue.
Is the coolant leaking from the fittings or is it leaking from a different part?
Unfortunately you do need to return the entire card for RMA and it won't be possible to replace just a part of the card.
In this case we cannot offer any service.
The reason is that you modified the card and by this it got damaged.
Therefore the manufacturer will not offer any service for us and so we cannot offer anything to you.
We hope for your kind understanding.