a seller has banned me from buying for no reason, What can do about this?

[pgnic]

A seller who I have spent a lot of money with suddenly changed their policy regarding combined shipping. When I asked for an extension on the three day payment to continue to bid on the other item they were not helpful and opened an unpaid item case. I paid immediately and then they suspended my buying with them and I have not received the item I originally purchased. Other than leaving negative feedback, what can I do? They are acting unethically and punitive in my opinion. 

[femmefan1946]

and I have not received the item I originally purchased.

This is the first thing to deal with.

How long has it been since payment?

If it has been more than 20 days from North America (30 days from Asia), go to the Resolution Centre at the bottom of this page and open an Item Not Recieved dispute.

You have already been in communication with the seller so just go to the Claim part.

If after receiving either the item or the refund, you can leave feedback, remember that the most effective feedback is calm and factual.

'Longtime customer Blocked after asking for combined shipping." would cover it. Your past feedback for him will show that you have been buying.

I can't think of any good reason for a seller to Block a repeat customer, especially if the request was to continue buying. Either the seller has lost the point of selling or you left something out. 

Is this the seller for whom you left seven FB, two of them neutral and one a soft positive?

[momcqueen]

This might not be what you think it is.

Firstly, many large sellers use the Unpaid Item assistant to open and close their Unpaid cases and those are set to do so automatically. As a buyer, you cannot assume any extension will be granted. Sellers set their terms, buyers just abide by them. Ebay facilities this. 

Secondly, those same automatic blocks can be used to prevent a buyer from purchasing or bidding on the seller's choice of 'too many items at once' so if you had, for example, three items awaiting payment plus were trying to bid on another seven, you may be auto-blocked from the seventh. 

Or just blocked, period. Manually and on purpose. For whatever reason. I think you assume the latter has happened but it is likely it's really a combination of the first two. 

How long has it been since you paid for your first item(s)?