[Tom Edgerton]

I would drop the grandmother a note (include your business card) saying that you have made contact with the mother, appreciate her participation in the auction, and leave it at that. If the grandmother has any influence, she can make it happen. If she doesn't--and it sounds like she doesn't beyond a point--it won't.

Sounds like the mother isn't interested in playing. Sometimes it happens that way.

Best--TE