Hi zeon-rat,
Based on the information provided: there are no definitive details that indicate a technical issue on the side of eBay. You seem to just be describing network latency with a likely combination of bid sniping. I will explain it this way: When you load, interact-with, or input data onto the internet, that information needs to get from point A to point B, or from point B back to point A. It is like a conversation, although more accurately can be described as a mail delivery service that can deliver, receive, and transport messages up until the speed of light. However nothing can get rid of the limitation of having to travel that distance. Speed, distance, and the time it takes for arrival are all interdependent on each other. If one changes, the other two will simultaneously be affected. WiFi is a wireless communication technology that relies on signal transmission. This is nothing more than an energized wave who's properties carry the data. Just like how light can reflect its direction on a mirror, there are plenty of physical objects that can obstruct a signal. Objects like metal, rooms, other signal generating devices, are just a few examples of common culprits that can interfere with wireless communications.
Unless you were to have a personal, direct-tunneled connection with the server, data almost never goes straight from A to B. The data travels to multiple destinations (called "hop's") that essentially give it directions to eventually end up at destination B (like eBay dot com).
You are likely getting outbid because you are initiating a time-dependent interaction on a device that has to first transmit that signal through the air to a modem/router. You know how you see lighting before you hear the thunder? That is because the audible signal the strike generates moves far slower than a beam of light. Now apply this to a live auction in the final 30 seconds. In this case, you are thunder and that winning bidder that is hard-wired to fiber optic connection is lightning (literally). There are also programs that can bid for you at the last second, but people who understand networking know that a program on its own is not enough to overcome the limitation of latency. Too many variables affect this, and the number of affecting variables can only be determined for a single point in time. The program needs to run on high-specc'd hardware and in addition needs a very powerful router with an extremely well-optimized routing table to refer data toward a specified server.
That time you won an auction at work on "SIM" data could be explained by nothing more complicated than being in close proximity to one of your phone carrier's cell towers. Although in conclusion: three examples aren't enough to be able to attribute any cause/effect relationship to explain why you're not getting in the final bid. I suggest you do your bidding on a hard-wired connection or just simply account for these millisecond values of latency when you do bid at the "last second."
