I think it is a very noble thing of you to go
above and beyond to try and fix this.  I am very
sorry to hear that something so unpleasant had to
happen :(

I have bought a cel from you before, the packaging
was great and the cel was completely safe.

When I ship a cel I usually will put it inside of
one of those flimsy priority mail paper envelopes
so that no tape or glue from the priority box gets
on it.  Then I will put it in the smaller priority
box (flat not opened).  I cut off the side flaps
that do not have glue on them and fold over the
ones that do have glue, sealing the sides of the
envelope.  I then place it in the bigger priority
box.  If the cel is not oversized this method
works very well to keep the cel safe.  I do almost
the same thing with slightly oversized cels, the
only difference is that you can't seal both of the
ends off so you have to be careful to protect the
cel from the exposed glue.

Sorry for my long rant, I hope this helps, I read
about this method a while ago and it works very
well.  Now this is the only way I will send a cel.