As mentioned above use the online browser option. It is not eBay thing, but as every app goes through is update process to eliminate glitches, enhance features etc. Same thing with your phone, Apple updates its operating system for similar or added features. Eventually old technology becomes obsolete and not worth programming time and money on it.
As long as you can do your functions online, no problem but eventually your iPad Air will become obsolete. That’s how they make their money, simple supply and demand. The work around will only last for so long until it’s time for you to upgrade. I feel your frustration as in have an older iPad that I used for games only until entirely the games upgrades made it non functional for me. It’s great for little kids to watch videos and so forth, but that’s about it.
