You could have a bad power brick. The iPhone charger won't put out enough power for the iPad (it will trickle charge but will register as not charging). I think the last hail mary you could try is getting a replacement brick....most retailers should have them, I know walmart does - and if it turns out to not be the brick, you should be able to easily return it.
If you try a different brick and if your ipad is totally dead it may take up to half an hour to get any sign of life.
Using the battery level meter in this manner is comparable to using your car's fuel gauge to calculate miles per gallon. The only thing that matters is the total amount of operating time from full charge to auto-shutdown.
Use the wall-mount charger that came with the iPad and charge overnight. Admittedly the labeling is hard to read but, if you use a magnifier and squint your eyes, you'll see "Output 5.1V, 2.1A." The symbol between volts and amps is the symbol for DC. Do NOT use an iPhone charger. Do NOT use an iPod charger. Do NOT use a computer's USB port. Then, operate it normally until auto shut-down (ignore any low level alerts that may appear). An irony is that doing that test to determine the total operating time is also the exact procedure necessary to calibrate the battery level meter.
I'm not claiming that you do not have a problem. I am stating, however, that we don't yet know whether or not a battery problem exists.
Use Your iPad Regularly
For proper reporting of the battery’s state of charge, be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down).
Elsewhere, Apple elaborates and explains that two half-discharges (or four quarter-discharges, etc.) equals one full discharge.
As I originally stated I used the wall charger that came with the iPad overnight in an attempt to charge it - no charging occurred.
Using the iPhone charging brick was a last resort to try to determine whether it was the charger or the iPad at fault.
Having managed to speak to someone at Apple it sounds like either the lightening cable or the iPad itself. Getting 2 broken iPads in a row doesn't give me much confidence in this product.
May or may not be the iPad if it's the cable. Not dismissing your frustration, because I'd be right there with you if I were in your shoes.
I hope it's something as simple as a cable because you can get that resolved before you need to leave (depending on your time zone and how late it is)
Then if the cable on your replacement iPad is bad, you can take it back to the apple store when you return and get them to replace it with a new one.
Just to close this out - the iPad was faulty, has now been replaced by Apple via a postal return system after I got back to Miri - I spent a day of my holiday travelling to an Apple shop only to be told it failed the diagnostics and they probably wouldn't be able to get a replacing before I left.
Very long drawn out and frustrating - took around a month in total from spending the money to having a working ipad in my hands.