I have been having this problem (am using a PC). Contacted ebay yesterday: lovely ebay person was originally told by her senior to tell me that my messages HAD all gone through, despite me being able to see that they hadn't (and they are not there if I download all the 'sent' message files from ebay). Eventually, the senior saw what I meant and I was told that the problem has been escalated.
"I have just checked with my technical team and they have confirmed me that there is an issue going on the site that members are not able to see the message from their end. However I am escalating the issue to my higher authorities against is that if there is any issue it will be solved at the earliest.
I am certain that it is not a problem with receiving ebay messages but with sending them.
It does seem to be PC based and the best proof I can suggest for anyone to give to ebay that their messages are NOT being sent is to go to 'Messages' and then under 'More Options' go to 'save your messages' and download the files as either EML or HTML. I did this earlier and can see clearly that only one message per day has been sent from my ebay account the last few days. I TRIED to send well over 50.
