Hi,
I saw your message on badbuyerlist.org about item #270852614682 and the negative feedback you received. Please report them to ebay right away. Ebay does not allow any buyer to open a case with out contacting the seller first. You can block this buyer from ever buying from you again in the block bidders section on your my eBay page.
Also, you can check a buyers feedback you can cancel their bid if you check feedback and if they have left too many negative feedback. To cancel bids your item must be in an auction form.
If this buyer is doing something fraudulent and he may be due to all the negative feedback he has left for other sellers he may be doing something ebay does not allow. Contact ebay and report the buyer for theft and fraud.
Do you have proof of delivery? If you can prove that the item was delivered, contact ebay and report this buyer. Theft is not tolerated by ebay.

It appears that reginarbuy tries to steel items if you do not provide tracking. Below is a positive feedback were some other seller left a follow up stating that the buyer is a scammer. I would contact all the sellers and ask them what happened to them and contact ebay with your findings. Also, ask the other sellers to contact ebay and report fraud.

I know this sounds like a lot of work but, it's important to report people like this.

Thanks for buying! Seller: Member id yfguitarist ( Feedback Score Of 841) Jan-03-12 14:47
■Follow-up by yfguitarist (Jan-19-12 22:37):
Buyer is a scammer! Make sure you get a tracking number!