Legally, there can only be one offer on the table. So there is no such thing as "counter-offer" it's I offer, you declined, you offer, etc. This is how offer works, here on the web or in real life, FYI.
Offer / counter-offer? Audiogon rules
I am a seller. I receive an offer. I immediately counter-offer. The potential buyer declines it. Is the buyer still bound to his original offer for the orignal 48 hrs.?