My nextbook will not charge with the adapters I've bought to replace the damaged one.

If it's not much bother really, your bes option is to take the next book replaced for you back and have it changed AGAIN; only this time, you must stay with them for the battery to fully charge, wait another one hour plus with your next book powered on and see if battery drains within one hour
In addition, check to see.whether the nextbook shuts down at all WHILE YOU ARE WITH THEM.

Only way to prove your claims, and confirm the replaced nextbook (3rd one) really works, lasts and meets your expectations.

Otherwise, you may have to request for a refund of your money or opt for another similar device as an exchange for the defective nextbooks

sounds like the battery is not charged up or taking a charge, check to see if the adapter is putting out voltage at the plug/pins.

This shows you where it is and how to replace it Nextbook 8 Battery Replacement

unless you have a very way out machine all power adapter charges are wired the same way
all you need is the correct fitting to go into your machine

contact the company you bought it from and get them to repair or replace under guarantee.

did you buy the battery brand new? of was it used? if used then that is what you should expect.. if new.. I would definitely return it.
try to let it run down power off the netbook and then restart if still only 10 minutes RETURN IT.

check our blog: SoftwareVariations.blogspot.com for other tips

Are you sure it's fully charged (like for 12 hours)? If so, try holding down the power button for at least 10-15 seconds, maybe more. Sometimes that works.

Every tablet has a button sequence, the reason being for a fresh restart. Either you unplugged it before full recharge, or didn't use proper charging adapter or cable.
There is a solution to avoiding this but first get tablet started by:
Hold power button and volume up button for eight seconds, release and hold power button again, tablet should turn on.
If not, do the opposite hold power button, volume down for eight seconds, then power button. You need to do this with proper adapter and charger you tablet came with plugged in. You may also need to do this more than once.
Once your tablet has started up, the way to avoid this is to swipe right on screen until you see settings app, should be round looking similar to a sprocket, or clock gear.
Open settings / display / sleep. I set mine for 30 mins.
Now you no longer need to power off you tablet manually, thus skipping the button sequence process.After unplugging from charge adapter you will still need to press power button to start.
Hope this helps I have yet to have this problem again, and remember to always let your tablet fully charge before disconnecting.