Forced to a transaction with an ebayer just after a first disappointment.

[beudie]

  1. I have concluded a previous transaction with this ebayer, where the result was a surprising low value for money for this type of collectors’ items.  But in the meantime, I had given my (winning) bid to another similar offer by the same ebayer. I explained to him  (by email) that I was not satisfied, so I don’t want to complete the second transaction with him. He offered (ironically) to improve the goods, but I am really not convinced.   Now he makes an eBay case, claiming that I am late with the payment, in a way forcing me to conclude the transaction.
  2. I am only an occasional buyer, ebay member since several years, with a 100% rating. I don’t want to risk my rating, that’s why I am still reluctant to give this seller a negative rating, in fear that he’ll reciprocate.   I would be grateful if you could give me advice on how to handle the issue.  

many thanks