Ann Shipman, There could be a few reasons for your device not charging and powering on. Faulty charger/cable, faulty battery, faulty charge port/connection etc., you could try a factory reset as described in 1st link below. Other links may help in trouble shooting your device if reset does not work. Good luck.
I hope this helped you out, if so let me know by pressing the helpful button.
http://www.femitechservices.com/2016/04/24/the-tagital-t7x-tablet-hard-reset-and-more/
https://www.youtube.com/watch?v=DSGAHFsnqaU
[[Tagital T7X Troubleshooting]]
[guide|60326]
[guide|57029]