I'm a buyer, but find ebay messages often fail to go through. It can and has strained relations between self and seller.
With all the anxiety inherent to ebay transactions, particularly recently, it's easy for a seller to reach the conclusion the buyer is dragging the chain or doesn't intend to follow through.
I've sent emails almost straight after the conclusion of the auction, seeking bank or pick-up details. A day seems a long time sometimes, especially when you want to pay and worry that the seller will be getting antsy. So I'll send another email via ebay messages, seeking payment and pick-up details. And again, nothing.
By the time a buyer finally gets through to a seller sometimes, it's to discover the seller is a bit terse, or at least not friendly. Which puts the buyer's back up, because they've tried to do it right.
Nowadays, as a buyer, I have no hesitation in seeking the seller's contact details from ebay without too much delay. Then I contact the seller and explain that I suspect my ebay messages seeking info have not been forwarded. Gets things moving and assures the seller there's someone genuine on the other end of that transaction. At the same time, not all sellers appreciate being contacted direct by the buyer .. and again, some of them get a bit terse or defensive.
I've come to regard it as one of the hazards of ebay transactions, where even a buyer can be put in the position of 'being wrong if you do and wrong even if you don't'.
It would be great if ebay would ensure that communication between buyers and sellers was allowed to proceed unimpeded .. would save a lot of tension all 'round.