Does that buyer violate any rules?

[two1370]

I got an offer from a big buyer (at least much bigger than me). That buyer is a seller as well - sells similar/related items
After that I sent a counter offer.

In several hours at the same moment (within one minute) I got 2 notification:
1. My counter offer is declined 
2. The item is sold to another buyer but no payment made. The buyer was created 2-3 days ago.

Now that listing is not available for sale and will not be available for a while.

The connection between those 2 accounts is obvious.

So, my questions are:

What can I do in situations like this?
What can I do to prevent that?

Any advice and suggestions would be much appreciated!

[sew734]

After 48 hours file an unpaid item dispute.   Close the dispute when you are allowed to do so.

[orangehound]

If you are convinced that this member is purposefully tieing up your item ...

• Block both accounts
• Relist the item with a new listing.
• Do not correspond with the member.
• File an unpaid item request when you are able.

[luckythewinner]

The connection between those 2 accounts is obvious.

What is the connection and what makes it obvious? 

That buyer is a seller as well - sells similar/related items

If that is the case he is not very bright. Buying and selling on the same account exposes you to possible retaliation. 

What can I do in situations like this? What can I do to prevent that?

There is nothing you can do to prevent a buyer from buying your items if you do not know the buyer's account beforehand. 

[dk0]

You can require immediate payment on buy it now items.  (Actually, I thought that had become the default.)

[ga-8370]

---

@two1370 wrote:

at the same moment (within one minute) I got 2 notification:
1. My counter offer is declined 
2. The item is sold to another buyer but no payment made. The buyer was created 2-3 days ago.

---

Um, when an item is sold, all pending offers are canceled.

[femmefan1946]

I think the problem is that an Unpaid Item Dispute takes six to eight days to close, taking the product off the market for a week.

I agree, open the UID as soon as you can (48 hours if you are in the USA), close it as soon as you can (another 96 hours) and relist.

Block both accounts.

Use Immediate Payment Required on all Fixed Price listings.

[candd205]

No matter how you feel about any connection, don't relist the item until you have completed the Unpaid Item process. The seller can buy it again under a third name, and then pay on both, leaving you with a problem when you can't mail both.