I'd say let it go, it just seems that the seller has no interest in selling the design to you. for what reason i dont know but that's the sellers choice.
in this situation you should just move on.
(if this isn't in the right place, let me know and i'll move it!)
About last week, an artist who I've been following for a while started a large purge of their ocs and i jumped on the chance to bid/claim one that i'd been eyeing. they're still fairly active,other people have claimed their adopts and "won" the auctions as well, and a few days ago after no reply i messaged them about claiming the chara for full price. still no reply, and when i commented on an unrelated post they replied fairly quickly. I think I was kind to her when i tried to get in contact, and as far as i know by checking their toyhou.se they still have her up for sale. should i just give up ?? i've been dying to get her ;-; please let me know if you have any advice!!! i appreciate anything you guys can say to help~